jonh deere 690e lc hydraulic test manual tm1508

Tests

90202514

TM1508 (12JUL05) 9020-25-14 690E LC Excavator Operation and Tests080805

PN=386

Section 9025Hydraulic System

Contents

Page Page

Group 05—Theory Of Operation Boom, Regenerative and Anti-Drift ValvesHydraulic System Components—(Serial No. Schematic . . . . . . . . . . . . . . . . . . . . . .9025-05-58

—556935) . . . . . . . . . . . . . . . . . . . . . . . . .9025-05-1 Arm, Regenerative and Anti-Drift ValvesHydraulic System Components—(Serial No. Schematic . . . . . . . . . . . . . . . . . . . . . .9025-05-59

556936—) . . . . . . . . . . . . . . . . . . . . . . . . .9025-05-2Control Valve Manifold

System Controller . . . . . . . . . . . . . . . . . . . . .9025-05-3Operation (SN —556935) . . . . . . . . . . . .9025-05-60

Switch Panel 2 . . . . . . . . . . . . . . . . . . . . . . .9025-05-4Operation (SN 556936—) . . . . . . . . . . . .9025-05-62

Hydraulic System Operation—(Serial No.Arm Cylinder Restrictor . . . . . . . . . . . . . . . .9025-05-64

—556935) . . . . . . . . . . . . . . . . . . . . . . . . .9025-05-8Boom Cylinder Restrictor (SN 556936—Hydraulic System Operation—(Serial No.

). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9025-05-66556936—) . . . . . . . . . . . . . . . . . . . . . . . .9025-05-10Control Valve SectionsControl System . . . . . . . . . . . . . . . . . . . . . .9025-05-12

Operation. . . . . . . . . . . . . . . . . . . . . . . . .9025-05-68Pilot Circuit . . . . . . . . . . . . . . . . . . . . . . . . .9025-05-13Neutral. . . . . . . . . . . . . . . . . . . . . . . . . . .9025-05-70Pilot Pump . . . . . . . . . . . . . . . . . . . . . . . . .9025-05-16Starting to Move . . . . . . . . . . . . . . . . . . .9025-05-72Pilot Filter . . . . . . . . . . . . . . . . . . . . . . . . . .9025-05-17Full Actuation. . . . . . . . . . . . . . . . . . . . . .9025-05-74Engine Speed Control ActuatorCombined . . . . . . . . . . . . . . . . . . . . . . . .9025-05-76Slow Idle . . . . . . . . . . . . . . . . . . . . . . . . .9025-05-18Swing Control Valve . . . . . . . . . . . . . . . .9025-05-78Fast Idle . . . . . . . . . . . . . . . . . . . . . . . . .9025-05-19

Circuit Relief and Anticavitation Valve . . . . .9025-05-80 9025Manual Override . . . . . . . . . . . . . . . . . . .9025-05-20Make-Up Valve . . . . . . . . . . . . . . . . . . . . . .9025-05-82Pilot Pressure Regulating Valve (SN —Return Manifold (SN 556936—) . . . . . . . . .9025-05-84556935) . . . . . . . . . . . . . . . . . . . . . . . . . .9025-05-21Boom Regenerative Valve (SN 545157—Pilot Pressure Regulating Valve (SN

556935) . . . . . . . . . . . . . . . . . . . . . . . . . .9025-05-86556936—) . . . . . . . . . . . . . . . . . . . . . . . .9025-05-22Arm Regenerative Valve (SN 546277—Pilot Shut-Off Valve. . . . . . . . . . . . . . . . . . .9025-05-24

556935) . . . . . . . . . . . . . . . . . . . . . . . . . .9025-05-92Pilot ControllerArm Regenerative Valve (SN 556936—) . . .9025-05-99Neutral. . . . . . . . . . . . . . . . . . . . . . . . . . .9025-05-25Anti-Drift Valve, Arm and Boom. . . . . . . . .9025-05-104Metering . . . . . . . . . . . . . . . . . . . . . . . . .9025-05-26Swing Torque Control Valve Long Front (SNFull Stroke . . . . . . . . . . . . . . . . . . . . . . . .9025-05-27

—546276) . . . . . . . . . . . . . . . . . . . . . . .9025-05-108Dig Pilot Check Valve . . . . . . . . . . . . . . . . .9025-05-28Swing Torque Control Valve (SNDual Solenoid Block . . . . . . . . . . . . . . . . . .9025-05-30

546277—) . . . . . . . . . . . . . . . . . . . . . . .9025-05-110Swing Brake Release Solenoid . . . . . . . . . .9025-05-32Pressure Control Manifold (SN —Swing Motor . . . . . . . . . . . . . . . . . . . . . . . .9025-05-34

556935) . . . . . . . . . . . . . . . . . . . . . . . . .9025-05-116Swing Crossover Relief ValveControl Valve Manifold (SN 556936—) . . .9025-05-118Normal Operation . . . . . . . . . . . . . . . . . .9025-05-36Power Boost Solenoid Actuated (SN —Relief Operation. . . . . . . . . . . . . . . . . . . .9025-05-38

556935) . . . . . . . . . . . . . . . . . . . . . . . . .9025-05-120Swing Stop Cushion Valve (SN 546277—Power Boost Solenoid (SN 556936—). . . .9025-05-122). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9025-05-41Load Sense System Relief Valve . . . . . . .9025-05-124Swing Gearbox . . . . . . . . . . . . . . . . . . . . . .9025-05-48Safety Relief Valve . . . . . . . . . . . . . . . . . .9025-05-126Control Valve and ManifoldMain Pump (SN —559602) . . . . . . . . . . . .9025-05-128Component Location (SN —556935) . . . .9025-05-50Main Pump (SN 559603—) . . . . . . . . . . . .9025-05-130Schematic (SN —556935) . . . . . . . . . . . .9025-05-52Pump Displacement Solenoid (SN —Boom, Swing, and Arm Control Valve

559602) . . . . . . . . . . . . . . . . . . . . . . . . .9025-05-132Component Location (SN 556936—) . . . .9025-05-54Pump Displacement Solenoid (SNSchematic (SN 556936—) . . . . . . . . . . . .9025-05-56

559603—) . . . . . . . . . . . . . . . . . . . . . . .9025-05-133Control Valve and ManifoldSwing and Torque Control Valves

Schematic . . . . . . . . . . . . . . . . . . . . . .9025-05-57 Continued on next page

TM1508 (12JUL05) 9025-1 690E LC Excavator Operation and Tests080805

PN=1

Contents

Page Page

Pump Regulator Control Valve Spool Stop Screws . . . . . . . .9025-20-16Control Valve Spool Stop Screws—LongMinimum Displacement (SN —

559602) . . . . . . . . . . . . . . . . . . . . . . .9025-05-134 Front . . . . . . . . . . . . . . . . . . . . . . . . . . . .9025-20-20Minimum Displacement (SN 559603—

) . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9025-05-136 Group 25—TestsJT05801 Clamp-On Electronic TachometerFixed and Maximum Displacement (SN —

559602) . . . . . . . . . . . . . . . . . . . . . . .9025-05-138 Installation . . . . . . . . . . . . . . . . . . . . . . . . .9025-25-1JT05800 Digital Thermometer Installation . . .9025-25-1Fixed and Maximum Displacement (SN

559603—) . . . . . . . . . . . . . . . . . . . . .9025-05-140 JT02156A Digital Pressure And TemperatureAnalyzer Installation. . . . . . . . . . . . . . . . . .9025-25-1Pump Neutral Control . . . . . . . . . . . . . . . .9025-05-143

Pump Low Pressure Control . . . . . . . . . . .9025-05-147 Hydraulic System Warm-Up . . . . . . . . . . . . .9025-25-2Hydraulic Pump Start-Up. . . . . . . . . . . . . . . .9025-25-3Pump High Pressure Control. . . . . . . . . . .9025-05-151

Return Circuit . . . . . . . . . . . . . . . . . . . . . .9025-05-155 Swing Motor Start-Up . . . . . . . . . . . . . . . . . .9025-25-4Swing Brake and Gearbox Start-Up . . . . . . .9025-25-4Drain Circuit . . . . . . . . . . . . . . . . . . . . . . .9025-05-159

Reservoir. . . . . . . . . . . . . . . . . . . . . . . . . .9025-05-162 Hydraulic Oil Filter Inspection . . . . . . . . . . . .9025-25-5Hydraulic Oil Cleanup Using PortableCylinder. . . . . . . . . . . . . . . . . . . . . . . . . . .9025-05-163

Filter Caddy . . . . . . . . . . . . . . . . . . . . . . . .9025-25-6Hydraulic Oil Cleanup Using Clean-UpGroup 10—System Operational Checks

Hydraulic Operational Checks . . . . . . . . . . . .9025-10-1 Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9025-25-7Pilot Pressure Regulator Valve . . . . . . . . . .9025-25-10Hydraulic System Checks . . . . . . . . . . . . . . .9025-10-1

Control Valve Checks . . . . . . . . . . . . . . . . . .9025-10-8 System Relief Valve . . . . . . . . . . . . . . . . . .9025-25-12Power Boost Solenoid Valve . . . . . . . . . . . .9025-25-14Manual Override Valve Checks . . . . . . . . . . .9025-10-9

Cycle Time Checks . . . . . . . . . . . . . . . . . . . .9025-10-9 Dig Function Circuit Relief Valve (SN —556935) . . . . . . . . . . . . . . . . . . . . . . . . . .9025-25-16Swing Brake Checks . . . . . . . . . . . . . . . . . .9025-10-13

Dig Function Circuit Relief Valve (SN556936—) . . . . . . . . . . . . . . . . . . . . . . . .9025-25-19Group 15—Diagnostic Information

Hydraulic System . . . . . . . . . . . . . . . . . . . . .9025-15-1 Pump Displacement Solenoid Valve . . . . . .9025-25-22Load Sense Valve Differential Pressure . . .9025-25-25Hydraulic Circuit Symbols . . . . . . . . . . . . . . .9025-15-7

9025

Component Location Manual Bypass Pressure ReducingValve . . . . . . . . . . . . . . . . . . . . . . . . . . . .9025-25-33Pilot Circuit (SN —556935) . . . . . . . . . . . .9025-15-9

Main Hydraulic Circuit (SN —556935) . . .9025-15-10 Swing Motor Crossover Relief Valve . . . . . .9025-25-35Swing Torque Control ValvePilot Circuit (SN 556936—) . . . . . . . . . . .9025-15-12

Main Hydraulic Circuit (SN 556936—) . . .9025-15-13 Long Front (SN —546276). . . . . . . . . . . .9025-25-38(SN 546277—). . . . . . . . . . . . . . . . . . . . .9025-25-41Schematic

Main Hydraulic (SN —556935) . . . . . . . .9025-15-15 Control Valve Return Anticavitation CheckValve . . . . . . . . . . . . . . . . . . . . . . . . . . . .9025-25-44Main Hydraulic (SN —556936) . . . . . . . .9025-15-18

Control Lever Pattern Information . . . . . . . .9025-15-22 Reservoir Pressure . . . . . . . . . . . . . . . . . . .9025-25-46Oil Cooler Pressure Drop . . . . . . . . . . . . . .9025-25-47Pilot Controller Lines—John Deere

Pattern. . . . . . . . . . . . . . . . . . . . . . . . . . .9025-15-24 Pilot Pump Flow . . . . . . . . . . . . . . . . . . . . .9025-25-48Hydraulic Pump Test Using Flow Meter . . .9025-25-51Pilot Controller Lines—Standard Pattern

(SAE). . . . . . . . . . . . . . . . . . . . . . . . . . . .9025-15-26 Hydraulic Pump Test Using Cycle Time . . .9025-25-56Hydraulic Pump Case Drain Flow . . . . . . . .9025-25-57Cyclinder Drift . . . . . . . . . . . . . . . . . . . . . . .9025-25-60Group 20—Adjustments

JT05800 Digital Thermometer Installation . . .9025-20-1 Swing Motor Case Drain Flow. . . . . . . . . . .9025-25-64Swing Brake and Gearbox Lubrication andHydraulic System Warm-Up . . . . . . . . . . . . .9025-20-2

Lower Boom With Engine Stopped . . . . . . . .9025-20-4 Cooling Flow . . . . . . . . . . . . . . . . . . . . . .9025-25-68Auxiliary Function Circuit Relief Valve . . . . .9025-25-70Raise Boom With Engine Stopped . . . . . . . .9025-20-6

Swing Upperstructure With Engine Cycle Times . . . . . . . . . . . . . . . . . . . . . . . .9025-25-72Cycle Times For Long Front . . . . . . . . . . . .9025-25-75Stopped . . . . . . . . . . . . . . . . . . . . . . . . . . .9025-20-8

Pilot Shut-Off Valve Linkage . . . . . . . . . . . .9025-20-11 TM Worksheet 1 Of 7—690E LCExcavator. . . . . . . . . . . . . . . . . . . . . . . . .9025-25-77Arm Cylinder Restrictor (Rod End) . . . . . . .9025-20-12

Boom Cylinder Restrictor (Head End) (SNContinued on next page556936—) . . . . . . . . . . . . . . . . . . . . . . . .9025-20-14


PN=2

Contents

Page

TM Worksheet 2 Of 7—690E LCExcavator. . . . . . . . . . . . . . . . . . . . . . . . .9025-25-78




TM Worksheet 6 Of 7—690E LCExcavator Art (Serial No. —556935) . . . .9025-25-82

TM Worksheet 7 Of 7—690E LCExcavator Art (Serial No. 556936—) . . . .9025-25-83

9025


PN=3

Contents

9025


PN=4

Group 05Theory Of Operation

9025051

TX,9025,LG27 –19–23OCT97–1/1

Hydraulic System Components—(Serial No. —556935)

ENGINESPEED CONTROL ACTUATOR

SYSTEM CONTROLLER

SWITCHPANEL 2

CONTROLVALVE

PILOTSHUT-OFFVALVE

TO DIGAND PROPELPILOTCONTROLLERS

DUALSOLENOIDBLOCK

TO DIGPILOTCONTROLLERS

DIG PILOTCHECK VALVEBLOCK

TOPROPELPILOTCONTROLLER

PROPELPILOT CHECKVALVE BLOCK

PILOTFILTER

PILOTPUMP

MAINHYDRAULIC

PUMP

PUMP REGULATOR

MAGNETICPICK-UP

A

G

BD

K

L

O

P

Q

W

I

F

C

HYDRAULIC SYSTEM COMPONENTS (S.N. —556935)T8336AB

RSUPPLY OILS

PILOT OILT

TRAPPED OILU

RETURN OILV

SWINGBRAKERELEASE

PROPELSPEEDCHANGE

N

E

H

J

M

T83

36A

B–1

9–28

OC

T97


PN=389

Theory Of Operation

TX,9025,LG28 –19–27AUG97–1/1

Hydraulic System Components—(Serial No. 556936—)

HYDRAULIC SYSTEM COMPONENTS—(SERIAL NO. 556936— )X

TRAPPED OILV

RETURN OILW

PILOT OILU

SUPPLY OILT

DUALSOLENOIDBLOCK

SWINGBRAKERELEASE PROPEL

SPEEDCHANGE

C

A

B

J PILOTFILTER

MAGNETICPICK-UP

SYSTEMCONTROLLER

SWITCHPANEL 2

N BOOM, SWING, ARMCONTROL VALVE

G

F

PILOTPUMP

MAINHYDRAULICPUMP

TO PROPELPILOT CONTROLLER

D

ENGINESPEEDCONTROLACTUATOR

PUMPREGULATOR

P

PILOTSHUT-OFFVALVE

R


STO DIG PILOTCONTROLLERS

QTO DIGAND PROPELPILOTCONTROLLERS

H

I

PROPEL PILOTCHECK VALVE BLOCK

PROPEL, BUCKETCONTROL VALVE

O

M

K

L

E

T110427

T110427 –19–28OCT97


PN=390

Theory Of Operation

9025053

TX,902505,JV255 –19–22JUL92–1/1

System Controller Operation

T77

93A

H–1

9–22

JUL9

2

The control system is made up of hydraulic andelectrical circuits. The load sense circuit routes thehighest work port pressure to the hydraulic pumpregulator. A number of sensors monitor engine speed,switch panel 2 functions and pilot controller movement.This data is sent to the system controller in the form ofelectrical sensing signals. The system controller sendsa control signal to engine speed control actuator, pumpregulator displacement solenoid, swing brake releasesolenoid, travel alarm, power boost solenoid, andpropel motor speed change solenoid. The result isoptimum matching of hydraulic function speed andengine power level.

The system controller controls engine speed, enginerpm pulldown, and pump displacement. When rpmpulldown reaches the set point, the system controllersends a control signal to the pump regulator to reducethe load sense differential pressure that reduces thepump displacement.

The system controller also has on board diagnostics tomonitor wiring harness, connections, solenoids andsensors. Indicator lights on the system controller signalpossible problems. A test switch on the systemcontroller changes controller modes to check or adjustmodes.


PN=391

Theory Of Operation

902505

4

TX,902505,JV256 –19–24OCT97–1/3

Switch Panel 2 Operation

T76

92A

F–1

9–24

FE

B92


PN=392

Continued on next page

Theory Of Operation

9025055

TX,902505,JV256 –19–24OCT97–2/3

Switch panel 2 (Y) contains operator controls forengine power modes, auto-idle, swing brake release,work modes and propel speeds.

The operator may select four different power modes(engine speeds): “P” max. power (H), “E” economy(G), “L” light duty (X) or “I” low idle (W). Engine speedincrease (E) or decrease (F) switches can also bepushed which changes engine speed approximately 80rpm per push. If increase or decrease switch is helddown, engine speed will change at a rate ofapproximately 275 rpm per second. Indicator lights willchange as rpm moves from one power mode toanother.

Auto-idle (I) function reduces engine speedapproximately four seconds after pilot controllers arereturned to neutral. Operating any dig or propelfunction overrides auto-idle function and the enginereturns to the preselected power mode (engine speed).Auto-idle speed is same as “L” (light duty) powermode. If engine speed is at “I” (low idle) power mode,auto-idle will not increase speed to “L.” When auto-idleis activated, the auto-idle indicator will come ON.Power mode indicator “P” or “E” will stay lit even whenengine is running at auto-idle speed.

Swing brake release (J) function allows the operator torelease the swing brake electronically. The swingbrake will remain released as long as circuit isactivated. The indicator light will be ON indicatingswing brake is released. When engine is stopped, thesystem controller will automatically default the functionto normal swing brake mode.

The operator can select four different work modes:“PR” precision (K), “EC” economy (R), “G” general (S),or “HD” heavy duty (T). The work mode select switchalso controls engine power modes and load sensedifferential pressure to control percent of pump flowavailable.

In “PR” (precision) work mode pump supply is 65% ofmaximum flow and “L” (light duty) power mode is

automatically activated. The operator can override thepreset power mode by pushing any of the other powermodes switches, but pump supply will remain at 65%.

In “EC“ (economy) work mode, pump supply is 80% ofmaximum flow. “E” (economy) power mode isautomatically activated.

In “G” (general) work mode, pump supply is 80% ofmaximum flow. “P” (max. power) power mode isautomatically activated and engine speed is 1950 rpm.

In “HD” (heavy duty) work mode, pump supply is atmaximum flow (100%). Load sensing differential willnot be electronically adjusted. “P” (max. power) powermode is automatically activated and engine speed is2150 rpm.

When machine is started, default for power mode is “L”(light duty), default for work mode is “PR” (precision).(Serial No. 544418—)—A work mode memory circuitis included. When circuit is connected, the systemcontroller will remember the work mode setting anddefault to that setting when machine is started. Thewiring leads (black and white) to connect circuit arelocated in the wiring harness in the right hand consolebelow switch panel 2. To connect, remove the whitetwo pin connector and replace with weather tightconnectors and a jumper wire.

When in “HD” (heavy duty) work mode, the operatormay select three different propel speeds by pushingthe propel speed decrease (L) or increase switch (M).

When in high speed propel, the propel motors willautomatically swash, controlled by system operatingpressure. Pump flow to propel motors is dependentupon work mode selected.

When in medium speed propel, the propel motors arefixed to maximum displacement. Pump flow isdependent upon work mode selected.


PN=393


Theory Of Operation

TX,902505,JV256 –19–24OCT97–3/3

When in low speed propel, the propel motors are fixedto maximum displacement. Pump flow is 75% ofmaximum. Engine speed is not affected. When in lowspeed propel and propel is actuated, “PR” (precision)

work mode is automatically actuated. When propelpilot controller is returned to neutral, machine willautomatically return to whatever work mode wasselected.

902505

6


PN=394

Theory Of Operation

9025057


PN=395

Theory Of Operation

902505

8

TX,9025,LG30 –19–27AUG97–1/2

Hydraulic System Operation—(Serial No. —556935)

PILOTSHUT-OFF

VALVE

DIG PILOTCHECK VALVE

BLOCK


PILOTFILTER

ARMCYLINDER

SWINGMOTOR

BOOMCYLINDER

BUCKETCYLINDER

PROPELMOTOR

PROPELMOTOR

ROTARYMANIFOLD

CONTROLLERMANUAL

OVERRIDEVALVE

SWING BRAKERELEASE SOLENOID

HYDRAULICRESERVOIR

PILOTPUMP

MAIN HYDRAULICPUMPS

ENGINE SPEEDCONTROL

ACTUATOR

REGULATOR

CONTROLVALVES

SWING

BOOM

BUCKET

LEFTPROPEL

PRESSURECONTROLMANIFOLD

ARM

RIGHTPROPEL

A B D

E

F

G

H

I

JK

L

M

N

Q

P

R

S

T

C

O

SUPPLY OIL

LOAD SENSE OIL

PILOT OIL

TRAPPED OIL

RETURN OIL

U

V

W

X

YZ

PROPEL SPEEDCHANGE

SOLENOID

PILOTCONTROLLERS

HYDRAULIC SYSTEM—(S.N. —556935)T111730

T11

1730

–19–

28O

CT

97


PN=396


Theory Of Operation

TX,9025,LG30 –19–27AUG97–2/2

The hydraulic system (Z) contains two separatecircuits. The pilot circuit is the control circuit for themain hydraulic circuit.

The main hydraulic circuit is a closed center, loadsensing system. Two variable displacement axialpiston pumps (M) produce supply oil (U) for the circuit.Pump displacement is controlled electronically by thesystem controller that provides constant torque controland constant speed sensing. Supply oil flows from thepumps to the main control valves (D).

The main control valves are pressure and flowcompensated. They route the highest load sense

pressure (V) to the pump regulator so the pump willsupply only the amount of oil required by a function orcombination of functions.

Load sensing improves fuel economy and reducesheat build-up because horsepower is not wasted onexcessive pump flow that is not being used.

From the control valves, supply oil is routed to thecylinders or motors. The swing motor (E) isbidirectional, fixed displacement, axial piston,swashplate design. The propel motors (I) are variabledisplacement and three propel speeds are available.

9025059


PN=397

Theory Of Operation

TX,9025,LG31 –19–27AUG97–1/2

Hydraulic System Operation—(Serial No. 556936—)

PILOTCONTROLLERS

DIG PILOTCHECK VALVE

BLOCK


PILOTFILTER

ENGINE SPEEDCONTROLACTUATOR

PILOTPUMP

MAINHYDRAULIC

PUMPS

REGULATOR

HYDRAULICRESERVOIR

CONTROLLERMANUAL

OVERRIDE VALVE

PROPEL SPEED

HYDRAULIC SYSTEM—(SERIAL NO. 556936— )

CHANGESOLENOID

SWING BRAKERELEASE

SOLENOIDSWINGMOTOR

LEFT PROPELMOTOR

ROTARYMANIFOLD

RIGHT PROPELMOTOR

BUCKETCYLINDER

BOOMCYLINDERS

BOOM

ARM

SWING

ARMCYLINDER

P

P

TT P

4

2

3

1

21

20

19

17

18

12 11

13

27

1415

16

10

8

9

7

6

22

23

24

25

26

SUPPLY OIL

LOAD SENSE OIL

PILOT OIL

TRAPPED OIL

RETURN OIL

T110297

PILOTSHUTOFF

VALVE

BOOM SWING, ARMCONTROL VALVE PROPEL, BUCKET

CONTROL VALVE

T110297 –19–28OCT97


PN=398

Theory Of Operation

TX,9025,LG31 –19–27AUG97–2/2

The hydraulic system (27) contains two separatecircuits. The pilot circuit is the control circuit for themain hydraulic circuit.

The main hydraulic circuit is a closed center, loadsensing system. Two variable displacement axialpiston pumps (14) produce supply oil (22) for thecircuit. Pump displacement is controlled electronicallyby the system controller that provides constant torquecontrol and constant speed sensing. Supply oil flowsfrom the pumps to the boom, swing, and arm controlvalves (4) and propel and bucket control valves (6).

The control valves are pressure and flowcompensated. They route the highest load sense

pressure (23) to the pump regulator so the pump willsupply only the amount of oil required by a function orcombination of functions.

Load sensing improves fuel economy and reducesheat build-up because horsepower is not wasted onexcessive pump flow that is not being used.

From the control valves, supply oil is routed to thecylinders or motors. The swing motor (10) isbidirectional, fixed displacement, axial piston,swashplate design. The propel motors (9) are variabledisplacement and three propel speeds are available.

90250511


PN=399

Theory Of Operation

90250512

TX,902505,JV259 –19–28FEB95–1/1

Control System Operation

Engine Speed Control Circuit

The control system allows the operator to chooseengine speed to match operating conditions andoperate engine as efficiently as possible.

System controller does not affect starting. The systemcontroller recognizes when the engine starts from theengine speed sensor and energizes the speed controlactuator for “L” (light duty) power mode setting. Lightduty power mode is maintained until machine operatorselects a different power mode, work mode, orchanges engine speed using speed increase or speeddecrease switches.

Exact engine speed is required by the systemcontroller for set engine speed and rpm pulldownregulation. A engine speed sensor (magnetic pickup)installed in the flywheel housing counts the flywheelteeth as the flywheel rotates.

The system controller sends a control signal (pulsewidth modulated current) to the engine speed controlactuator solenoid. The solenoid regulates the amountof pilot oil routed to the actuator that controls itsstroke. As the actuator moves, it controls the fuelinjection pump lever and engine speed. Engineinjection pump linkage must be adjusted properly toallow for full travel from slow to fast idle.

Engine Speed Sensing Circuit

The engine speed sensing circuit uses the enginespeed sensor (magnetic pickup) to sense actualengine speed and send a sensing signal to the systemcontroller. The controller calculates required pump

drive torque and sends a control signal to the pumpregulator that is also sensing load sense pressure(highest work port pressure). Pump flow rate iscontrolled to keep required pump drive torque at orbelow the engine torque level produced at maximumhorsepower.

If hydraulic functions are being operated, the pumpswash angle is allowed to increase until pump drivetorque equals the engine torque level at maximumhorsepower. Pump drive torque is directly proportionalto system pressure.

If engine power (rpm) is decreased, hydraulic pumpdrive torque may exceed the engine output torquecausing engine to stall. To prevent this, pump swashangle is adjusted to reduce pump drive torque.

Load Sense Circuit

The load sense circuit is used to bring the pump intostroke when a function is activated. Pump supplypressure is always higher than the highest load sensepressure. When all pilot controllers are in neutral, loadsense pressure is equal to reservoir pressure andpump outlet pressure is approximately 3447 kPa (34bar) (500 psi). When a function is first moveddifferential pressure is increased and pumpdisplacement is proportionally increased.

The engine speed sensor (magnetic pickup) tells thesystem controller when all available enginehorsepower is being used. As the load (pressure)increases the controller sends a signal to the pumpdisplacement solenoid to destroke the pump to preventengine overload.


PN=400

Theory Of Operation

TX,9025,LG32 –19–27AUG97–1/3

Pilot Circuit Operation

T110357

PILOTPUMP

PILOT CIRCUIT—(S.N. —556935)O

JDUALSOLENOIDBLOCK

RESERVOIR L

K ENGINE SPEEDCONTROL ACTUATOR


F

H

MAINHYDRAULICCONTROLVALVE


I SWINGMOTOR

ED

C

LEFT PILOTCONTROLLER

PILOTSHUT-OFFVALVE

RIGHT PILOTCONTROLLER

PILOT OIL

RETURN OILN

M

A

BPILOTFILTER

G

T110357 –19–28OCT97


PN=401

Theory Of Operation

TX,9025,LG32 –19–27AUG97–2/3

PILOT CIRCUIT—(S.N. 556936— )O

PILOT OILM

RETURN OILN

DUALSOLENOIDBLOCK

ENGINE SPEEDCONTROL ACTUATOR

APILOTPUMP

J

SWINGMOTOR

I

T110358

E

G

DLEFTPILOTCONTROLLER

RIGHTPILOTCONTROLLER

LRESERVOIR

BOOM,SWING,ARMCONTROLVALVE

PROPEL, BUCKETCONTROL VALVE

H

K

BPILOTFILTER

CPILOTSHUT-OFFVALVE

T110358 –19–28OCT97

The pilot pump (A) is a fixed displacement gear typepump. It is mounted on the end of the main hydraulic

pump and driven by the main hydraulic pump driveshaft.


PN=402

Theory Of Operation

90250515

TX,9025,LG32 –19–27AUG97–3/3

Pilot oil flows from the pilot pump through the pilot filter(B) to the pressure control manifold (H) on machines(Serial No. —556935), or from the pilot filter (B) to theboom, swing, and arm control valve (G) on machines(Serial No. 556936—). The pressure control manifoldor boom, swing, and arm control valve manifoldcontains the pilot pressure regulating valve. The pilotpressure regulating valve is shim adjustable. Pilot oil isused for power boost.

Pilot oil, from the pressure control manifold or controlvalve manifold, flows to the dual solenoid block (J) andto the pilot shut-off valve (C). The shut-off valve blockspilot oil from the left and right pilot controllers (D andE) and propel pilot controller when in the OFF position.With the shut-off valve ON, pilot oil flows to the pilotcontrollers.

The pilot controllers route oil to the pilot caps of themain hydraulic control valve (G) on machines (SerialNo. —556935) or to the boom, swing, and arm controlvalves (G) and to the propel and bucket control valve(H) on machines (Serial No. 556936—) to shift thespools. Return oil from the actuated spools flowsthrough the pilot controllers and shut-off valve to thereservoir (L).

The engine speed control actuator (K) receives pilot oiland contains a solenoid which is controlled by thesystem controller. Engine speed is controlled by pilotoil in the engine speed control actuator.

The dual solenoid block contains solenoids foroperation of propel speed change and one for swingbrake release. A manual override valve is also located

in the solenoid block. Opening the manual overridevalve allows the engine to run at “P” power mode (fastidle) and pump displacement will be approximately65%.

Return oil from all pilot functions is routed through thereturn filter in the reservoir.

(Serial No. 546277—)The swing stop cushion valve is fasten to the top ofswing motor (I). The Pst port line is connected, alongwith the swing brake release switch, to a tee fitting inthe S1 port of dig pilot check valve block (F). The Pzulport line is connected to a tee at the P port of dualsolenoid valve block (J). When swing is actuated, thepilot oil pressure signal is also sent from the S1 port toPst port to shift the pilot pressure spool in cushionvalve. When spool is shifted, pilot oil from the P portflows to the Pzul port to “charge” the cushion valvespool. (See Swing Stop Cushion Valve Operationin thisgroup.)

(Serial No. 550240—)An orifice is added to the return line of the enginespeed control actuator. The addition of the orificeimproves the stability of engine speed control actuator,reduces vibration of engine speed control linkage, andeliminates engine surging. The orifice is “captured” inthe connection of return hose end fitting to the teefitting at the top of main pump regulator.

(Serial No. 556936—)The main hydraulic control valve is replaced with aboom, swing, and arm control valve and a propel andbucket control valve.


PN=403

Theory Of Operation

90250516

902505,EE60 –19–21AUG91–1/1

Pilot Pump Operation

T67

11A

D–U

N–3

0MA

R89

The pilot pump (E) is a fixed displacement gear typepump. It is mounted on the end of the main hydraulicpump and driven through a splined coupler connectedto the drive shaft of main hydraulic pump. The gears

(B) are supported by bushings (D). Sealing plates onboth sides of the gears separate intake oil fromdischarge oil.


PN=404

Theory Of Operation

90250517

TX,902505,IJ135 –19–09SEP97–1/1

Pilot Filter Operation

P P

PILOT OIL

RESTRICTED PILOT OIL

PILOT FILTER

AF

G

B

A

G

B

A

G

E

G

J

K

L

I H I H

FROMPILOT PUMP

FILTERBYPASSSWITCH

PISTON

SPRING

SPRING

FILTERELEMENT

RELIEFVALVE

F

B

D

F

A

H

I

T7571AM CV

C

T75

71A

M–1

9–02

SE

P97

The pilot filter (L) removes contaminants from the pilotsystem oil. The filter housing contains a relief valve (H)and a filter bypass switch (B). The filter bypass switchis not used in this application.

Under normal operation, flow from the pilot pumpenters the inlet (A), flows through the filter element (F)and out the outlet (G).

As the filter becomes plugged, or when the hydraulicoil is very cold, the pressure differential between theinlet and outlet increases. Inlet pressure is sensed onone side of the valve (H) which opens against springforce (I) and outlet pressure. The pilot pump flow thenbypasses the filter. Extended operation in the bypassmode will cause damage to hydraulic system.


PN=405

Theory Of Operation

90250518

TX,902505,SS620 –19–09SEP97–1/1

Engine Speed Control Actuator Operation—Slow Idle

PISTONROD BOOT

SHIMSBUSHING

SPRINGPLATE PISTON SPRING

SOLENOIDPIN

SOLENOID

FROMPILOTPUMP

VALVEHOUSING

FROMCONTROLLERMANUALOVERRIDEVALVE

TORESERVOIR

A

T7544AC CV ENGINE SPEED CONTROL ACTUATOR

P PILOT OIL

B C D EF G H I

J

K

M

LNO

Q RETURN OILR

PISTON PIN

T75

44A

C–1

9–02

SE

P97

The engine speed control actuator (R) controls themovement of the engine speed control linkage tocontrol engine speed.

The actuator is controlled by the solenoid (K) whichreceives a signal form the system controller.

The solenoid (K) moves the solenoid pin (J). Theposition of solenoid pin (J) controls the position of thepin (I). This regulates pilot oil which controls theactuator stroke or how far the piston rod (A) moves.Piston rod (A) moves the linkage to the injection pump.

When the engine speed control actuator is notactuated, spring force (H) holds the pin open to allowoil to go to return (Q).

(Serial No. 550240—)An orifice is added to the return line to reservoir (O) ofthe engine speed control actuator. The addition of theorifice improves the stability of engine speed controlactuator, reduces vibration of engine speed controllinkage, and eliminates engine surging. The orifice is“captured” in the connection of return hose end fittingto the tee fitting at the top of main pump regulator.


PN=406

Theory Of Operation

90250519

TX,902505,SS621 –19–09SEP97–1/1

Engine Speed Control Actuator Operation—Fast Idle

PISTONROD BOOT

SHIMSBUSHING


SOLENOIDPIN

SOLENOID

FROMPILOTPUMP

VALVEHOUSING


TORESERVOIR

A

T7554AD CV ENGINE SPEED CONTROL ACTUATOR – FAST IDLE

P PILOT OIL

B C D EF G H I

J

K

M

LNO

Q RETURN OIL

PISTONPIN

R

T75

54A

D–1

9–02

SE

P97

When the actuator is in fast idle position (R), thesystem controller energizes the solenoid (K). Thesolenoid pin (J) moves out (left) to move pin (I). Thisallows pilot pump oil (P) to fill piston cavity (G).

When pressure builds, piston (G) moves piston (F).This moves piston rod (A) out against the bellcrankroller bearing which regulates how far the injectionpump lever moves for fast idle.

To maintain fast idle speed and to compensate forleakage, the solenoid (K) is constantly regulating theposition of pin (I). This is accomplished by the systemcontroller. The system controller monitors enginespeed and sends a signal to the solenoid (K). Thesolenoid pin (J) positions pin (I) to regulate the amountof pilot oil entering the actuator to maintain a constantengine speed.


PN=407

Theory Of Operation

90250520

TX,902505,SS622 –19–09SEP97–1/1

Engine Speed Control Actuator Operation—Manual Override

PISTONROD BOOT

SHIMSBUSHING


SOLENOIDPIN

SOLENOID

FROMPILOTPUMP

VALVEHOUSING


TORESERVOIR

A

T7554AE CV ENGINE SPEED CONTROL ACTUATOR – MANUAL OVERRIDE

P PILOT OIL

B C D EF G H I

J

KM

LNO

Q RETURN OIL

PINPISTON

R

T75

54A

E–1

9–02

SE

P97

If certain electrical system components malfunction,the operator can turn the manual override knob on thedual solenoid valve (located between the control valveand hydraulic reservoir) ON. This allows the machineto obtain fast idle and pump at about 65% flow forcontinued operation until repairs can be made.

Pilot oil (N) enters the actuator between piston (G) and(F). Pressure builds to the left and moves piston (F)which moves piston rod (A). This moves the fuelinjection lever to fast idle position. Injection pumplinkage travel is limited by a screw on the linkage.


PN=408

Theory Of Operation

90250521

TX,9025,LG33 –19–27AUG97–1/1

Pilot Pressure Regulating Valve Operation—(Serial No. —556935)

T111716

PILOT OIL

RETURN OIL

PILOT PRESSURE REGULATING VALVE—(S.N. —556935)K

I

J

SPRING

FROMPILOTPUMP

PISTON

SPRINGGUIDE

SHIMS

GUIDEPIN

HOUSING

RETURNTO CONTROLVALVE MANIFOLD

A

BC

E

F

G

H

D

T11

1716

–19–

28O

CT

97

The pilot pressure regulating valve (K) establishes pilotcircuit pressure. Valve is shim (F) adjustable.Regulating valve is located in the pressure controlmanifold which in mounted on the control valvemanifold. (See Pressure Control Manifold Operation inthis group.)

Pilot oil (I) from pilot pump (A) enters the end of theregulating valve and applies force against the face of

piston (C). The spring force holds the piston on itsseat. When pilot oil exceeds spring force, the pistonwill move off the seat and allow excess oil to flow toreturn through the control valve manifold (B).

Return oil is sent through the manifold to ensure thatthere is sufficient make-up oil for all functions.


PN=409

Theory Of Operation

90250522

TX,9025,LG34 –19–27AUG97–1/1

Pilot Pressure Regulating Valve Operation—(Serial No. 556936—)

T110359

PILOT OIL

RETURN OIL

I

J

K

FROMPILOTPUMP

PISTON

SPRINGGUIDE

NUT

HOUSING

RETURNTO CONTROLVALVE MANIFOLD

A

H

I

B SPRINGDC

SCREW

G

E

O-RINGF

PILOT PRESSURE REGULATING VALVE—(S.N. 556936— )

T11

0359

–19–

28O

CT

97

The pilot pressure regulating valve (K) establishes pilotcircuit pressure. Valve is shim (F) adjustable. Theregulating valve is located on the boom, swing, armcontrol valve manifold above the arm section. (SeeControl Valve Manifold Operation in this group.)

Pilot oil (I) from pilot pump (A) enters the end of theregulating valve and applies force against the face of

piston (C). The spring force holds the piston on itsseat. When pilot oil exceeds spring force, the pistonwill move off the seat and allow excess oil to flow toreturn through the control valve manifold (B).

Return oil is sent through the manifold to ensure thatthere is sufficient make-up oil for all functions.


PN=410

Theory Of Operation

90250523


PN=411

Theory Of Operation

90250524

TX,9025,SS789 –19–09SEP97–1/2

Pilot Shut-Off Valve Operation

A

B

C

D

F

G FROM PILOT FILTER

TO RESERVOIR

FROM PROPEL PILOT CONTROLLER

FROM RIGHT PILOT CONTROLLER

RIGHT PILOT CONTROLLER

PROPEL PILOT CONTROLLER

LEFT PILOT CONTROLLER

H

FROM LEFTPILOT

CONTROLLER

A

B

C

H

D

E

F

G

A

B

C

D

F

G FROM PILOT FILTER

TO RESERVOIR

FROM RIGHT PILOT CONTROLLER

RIGHT PILOT CONTROLLER

PROPEL PILOT CONTROLLER

LEFT PILOT CONTROLLER

H

FROM LEFTPILOT

CONTROLLER

FROM PROPEL PILOT CONTROLLER

E

L PILOT SHUT-OFF — OFF

I

PILOT SHUT-OFF — ON

T7428AC CV

PILOT OILJ

RETURN OILK

E

I

I

A

B

C

H

D

E

F

G T

7428

AC

–19–

02S

EP

97


PN=412


Theory Of Operation

TX,9025,SS789 –19–09SEP97–2/2

The pilot shut-off valve (I) blocks the pilot oil (J) fromthe pilot pump to the pilot controllers (A,B,C). In theON position, the shut-off lever is moved forward whichallows pilot oil from the pilot pump (G) to flow to pilotcontrollers (A,B,C). Return oil (K) from the pilotcontrollers (D,E,H) is open to the reservoir.

In the OFF position pilot oil is blocked at the shut-offvalve. Lines to the pilot controllers (A,B,C) and linesfrom the controllers (D,E,H) are open to return.

90250525

TX,9025,IJ55 –19–09SEP97–1/1

Pilot Controller Operation—Neutral

EB

J

IK

LEVER

PLUNGER

SPRING GUIDE

SPOOL

PISTONTO RESERVOIR

FROM PILOT PUMP

TO CONTROL VALVE

TO RESERVOIR

RETURN SPRING

BALANCE SPRING

SLEEVE

PILOT CONTROLLER - NEUTRALT7350BH P

K

G

H

A

B

C

D

E

I

J

I

RETAINER

F

SHIMS

N

PILOTOIL

L

RETURN OIL

M

O

T73

50B

H–1

9–12

AU

G98

Two hand operated pilot controller (right and left) areused to control the dig functions. Each controllercontains four valve assemblies, one for each directionof a function.

The pilot controller consists of the plunger (D), sleeve(F), spring guide (C), retainer (N), spool (B), piston (A),balance spring (G), shims (O), and return spring (H).

In neutral, the spool is pushed up by the return springto block oil from the pilot pump (K). With the spool up,the passage to the control valve (J) is connected to thereservoir (I).


PN=413

Theory Of Operation

90250526

TX,902505,IJ56 –19–09SEP97–1/1

Pilot Controller Operation—Metering

T7350CK

PILOT OILL

N

RETURN OILMPISTON A

SPOOL B

SPRINGGUIDE

C

PLUNGER D

E LEVER

F SLEEVE

G BALANCE SPRING

RETURN SPRINGH

TO RESERVOIR

TO CONTROL VALVEJ

FROM PILOT PUMPK

TO RESERVOIR I

E

B

K

I

J

I

PILOT CONTROLLER – METERING

T73

50C

K–1

9–06

MA

Y98

To meter a function, the lever (E) is moved slightly.This moves the plunger (D) and spring guide (C)against the balance spring (G) which moves the spool(B) down. The spool blocks the reservoir passage (I)and opens the passage from the pilot pump (K) tocontrol valve (J).

Pilot oil (L) also acts on piston (A) in the spool, movingthe spool up against the balance spring which closes

the passage to the control valve. This maintainspressure in the control valve passage according to theforce on the balance spring by the plunger. As thelever is moved further, the plunger applies more forceto the balance spring and the control valve passageagain increases in pressure to balance the spool.


PN=414

Theory Of Operation

90250527

TX,902505,IJ57 –19–09SEP97–1/1

Pilot Controller Operation—Full Stroke

PILOT CONTROLLER – FULL STROKE T7350CL

PILOT OILL

N

RETURN OILMPISTON A

SPOOL B

SPRINGGUIDE

C

PLUNGER D F SLEEVE

G BALANCE SPRING

RETURN SPRINGH

TO RESERVOIR

TO CONTROL VALVE

FROM PILOT PUMPK

TO RESERVOIR I

E

B

K

I

J

J

LEVER

I

E

T73

50C

L–1

9–02

SE

P97

When the lever (E) is moved to full stroke, the plunger(D) movement is transmitted directly to the spool (B).This forces the spool down connecting the passage

from pilot pump (K) with the passage to the controlvalve (J). Oil pressure to the control valve now equalspilot system pressure.


PN=415

Theory Of Operation

90250528

TX,902505,SS766 –19–09SEP97–1/1

Dig Pilot Check Valve Operation

DIG PILOT CHECK VALVET8429BE CV

E1,E2 F1,F2 G1,G2 H1,H2 I1,I2 J1,J2 K1,K2 L1,L2ORIFICE

SWINGBRAKERELEASESWITCH

AUTOIDLESWITCH

PILOT OIL

K

I

RETURN OILJ

A

B

CD

E

DIGPILOTCHECKVALVE

SPRING CHECKBALL

F

TO PST PORTSWING STOPCUSHIONVALVE(S.N. 546277 —)

G

TO Z2 PORTPRESSURECONTROLMANIFOLD

H

T84

29B

E–1

9–02

SE

P97

The dig pilot check valve (I) is located on the mainframe behind the right rear corner of cab. Access tothe valve is through the left service door behind cab.

The main function of check valve is to monitor pilotpressure in the dig function pilot circuit and send aelectrical signal to the system controller when any digfunction and swing function is actuated.

Pilot oil from the controllers enters the block throughports E1—L2 depending on the function being used.The pressure in the circuit forces the check ball (D) offits seat allowing pressure to reach the auto idle switch

(E) or swing brake release switch (A). An orifice (F) inthe passage to auto idle switch allows oil to bleed outof the circuit when the controllers are returned toneutral. In neutral all the ports are connected to return.

(Serial No. 546277—)The Pst port line (G) from the swing stop cushionvalve on swing motor is connected, along with theswing brake release switch (A), to a tee fitting in theS1 port of dig pilot check valve (I). When swingfunction is actuated, pilot oil pressure is sent to thecushion valve and a electrical signal to the systemcontroller.


PN=416

Theory Of Operation

90250529


PN=417

Theory Of Operation

90250530

TX,9025,LG35 –19–27AUG97–1/2

Dual Solenoid Block Operation

T111717 DUAL SOLENOID BLOCK M

K

L

ED

H

J

I G

A

F

C

BPROPEL SPEEDCHANGE SOLENOID

TORESERVOIR

FROM PILOTFILTER

TO PROPELMOTOR

TO SWINGBRAKE

TO SPEEDCONTROLACTUATOR

TO PUMPREGULATOR

SWING BRAKERELEASE SOLENOID

SYSTEM CONTROLLERMANUAL OVERRIDEVALVE

PRESSUREREDUCINGVALVE

E

H

I

J

F

A

B

C

G

PILOT OIL

RETURN OIL

D

EARLYMACHINES

T11

1717

–19–

28O

CT

97


PN=418


Theory Of Operation

9025TX,9025,LG35 –19–27AUG97–2/2

The dual solenoid block (N) contains the propel speedchange solenoid (A), swing brake release solenoid (B),system controller manual override valve (C) and pilotpressure reducing valve (D).

(Serial No. 538539—)For the system controller manual override valve (C), adetent was added and the style of knob was changed.

Pilot oil from the pilot filter (J) is routed to a commonpassage between both solenoids (A and B) andoverride valve (C). When a solenoid is actuated(shown), pilot oil is routed to propel motor (H) or toswing brake (G) or to both.

When system controller manual override valve isactuated, pilot oil is routed to engine speed control

actuator. The actuator increases engine speed to fastidle. Pilot oil is also routed to the pressure reducingvalve (D). The pressure reducing valve reduces pilotoil and routes the reduced pilot oil to the pumpregulator (E). The reduced pilot oil regulates pump flowto approximately 60—70% of maximum flow. If pilot oilwas not reduced, full pilot pressure would destroke thepumps to near zero flow. If pumps were run atmaximum stroke the engine would stall because therewould be more hydraulic horsepower demand thanavailable engine horsepower.

(Serial No. 556936—)The dual solenoid block is now located on the firewallnext to the cold weather start aid.

0531


PN=419

Theory Of Operation

90250532

TX,9025,DW1354 –19–23OCT97–1/2

Swing Brake Release Solenoid Operation

T7584AE SWING BRAKE RELEASE SOLENOID

PILOT OIL

K

I

RETURN OILJ

H

E

ACTIVATED

SOLENOIDVALVE

F

C

D

E

G

B

FROMPILOTPUMP

NEUTRAL

TO SWINGBRAKE

TORESERVOIR

SPOOL

COIL

A

F

D

D

F E

T75

84A

E–1

9–02

SE

P97

(Serial No. —556935)Swing brake release solenoid (K) is located on thedual solenoid valve block and is the solenoid closest tothe reservoir.

(Serial No. 556936—)The swing brake release solenoid is located in the dualsolenoid valve block and is the solenoid closest to theengine firewall.

During normal operation, the swing brake releasesolenoid is activated every time the swing pilot

controller is moved. A signal from the swing brakerelease switch to the system controller energizes theswing brake release solenoid to disengage the brake.The operator can choose to release the swing brakeall the time by pressing the swing brake release buttonon switch panel 2. The controller sends a signal toenergize a relay which energizes the coil. When thesolenoid is in neutral (G) pilot oil (I) from the pilotpump (F) is blocked from going to the swing brake (E).The line to the swing brake is open to reservoir (D).


PN=420


Theory Of Operation

TX,9025,DW1354 –19–23OCT97–2/2

When the solenoid is activated (H), the spool is pulledup, blocking the passage to reservoir and routing pilotoil to the swing brake. The swing brake is now

disengaged and will engage when the swing pilotcontroller is returned to neutral.

90250533


PN=421

Theory Of Operation

90250534

TX,902505,SS570 –19–09SEP97–1/2

Swing Motor Operation

T7543AB SWING MOTORL

SUPPLY OIL

RETURN OIL

J

K

VALVEPLATE

ROTOR

RETAINER

OUTPUTSHAFT

LOADSPRING

PISTON

SLIPPER

FIXEDSWASHPLATE

SEAL

A

B

C

H

I

E

F

G

D

T75

43A

B–1

9–22

SE

P97

A fixed displacement, axial position, swashplatedesigned motor is used. It is bidirectional so that theupperstructure can swing in both directions.


PN=422


Theory Of Operation

90250535

TX,902505,SS570 –19–09SEP97–2/2

The rotating group consist of a cylinder block and ninepistons (B) splined to the output shaft (F). Each pistonis fitted through a ball joint to a slipper (C). Theslippers slide on the incline of the swashplate (D) asthe rotating group turns. A retainer holds the slipperson the swashplate and the retainer itself is heldagainst the slippers by a load spring (A).

Oil from the control valve to the pistons is routed to themotor end cover and through a valve plate (I). Thevalve plate is prevented from turning by a dowel pin.

The pistons in one half of the rotating group, from thehighest point to the lowest, are being acted on bysupply oil from the control valve. For the pistons to bemoved out of their bore by the oil, they must movedown and around the incline of the swashplate. Thiscauses the cylinder block and output shaft to rotate.

The pistons in the other half of the cylinder block mustmove back into their bores as their slippers travel backup the incline of the swashplate. As these pistonsmove in, return oil flows from the cylinder block backto the control valve.

Pressure oil flows through the center of each piston tothe ball joint and to the face of the slipper forlubrication. Motor components operate in oil containedby the housing and excess oil flows through a returnline from the housing back to the reservoir.

(Serial No. 546277—)The swing stop cushion valve is fasten to the top ofswing motor (L). The Pst port line is connected, alongwith the swing brake release switch, to a tee fitting atthe S1 port of the dig pilot check valve. The Pzul portline is connected to a tee at the P port of the dualsolenoid valve.

The function of swing stop cushion valve is to releasethe pressure build up in the swing motor work circuitcause by the inertia of the upperstructure after thepressure becomes less than the swing crossover reliefvalves pressure setting. The release of pressure by thecushion valve after the swing crossover relief valvecloses is to achieve a cushioned stop and to preventthe back and forth movement of the upperstructure.(See Swing Stop Cushion Valve Operation in thisgroup.)


PN=423

Theory Of Operation

90250536

TX,902505,SS574 –19–09SEP97–1/2

Swing Crossover Relief Valve Operation

SUPPLY OILL

SWING CROSSOVER RELIEF-NORMAL OPERATIONT7474AC N

RETURN OILM

RETURN JADJUSTMENTSCREW

SPRING

PILOTPOPPET

I

H

K

G

F

E

D

C

B

A

ORIFICE

MAINPOPPET

PISTON

SPRING

SPRING

WORKPORTS

MOTORPORTS

T74

74A

C–1

9–15

SE

P97


PN=424


Theory Of Operation

TX,902505,SS574 –19–09SEP97–2/2

The swing crossover relief valves (N) are pilotoperated valves. They protect the work port circuit theyare in and relieve to the opposite work port. Bothvalves are located in a block that is bolted to the coverof the swing motor. The lines from the main controlvalves are connected to the block.

Work port pressure is sensed on the face of mainpoppet (D). The poppet is held on its seat by spring(F). Return oil from pilot poppet (H) is open to returnpassage (K). Pilot poppet is held on its seat by spring(I). Spring (I) is adjusted with adjustment screw (J).

90250537


PN=425

Theory Of Operation

90250538

TX,902505,SS581 –19–11MAY98–1/2

Swing Crossover Relief Valve Operation—Relief

RELIEF PRESSURE OILE

SWING CROSSOVER RELIEF-RELIEF OPERATIONT7479AP G

RETURN OILF

PILOTPOPPET

D

C

AMAINPOPPET

PISTON

B MAINPOPPET

T74

79A

P–1

9–02

SE

P97


PN=426


Theory Of Operation

TX,902505,SS581 –19–11MAY98–2/2

In relief operation (G), the relief valve opens in threesteps. In the first step, the pilot poppet (D) is opened.Flow restriction through the hollow piston (C) causesthe pressure in the cavity behind the main poppet (B)to decrease. In the second step of relief operation, thepiston (C) seats against the pilot poppet (D). Thisfurther reduces oil flow into the cavity and decreases

the pressure against the back side of the main poppet(B). The main poppet (B) opens in the third step ofrelief operation.

Relief pressure oil is routed to main poppet (A)opening it and providing crossover operation to preventmotor cavitation or allows oil to go to return.

90250539


PN=427

Theory Of Operation

90250540


PN=428

Theory Of Operation

90250541

TX,9025,GG1030 –19–09SEP97–1/6

Swing Stop Cushion Valve Operation (Serial No. 546277—)

T82

15B

A–1

9–03

JUN

94

A—Swing Motor D—Spring G—Pilot Pressure Spool I—Swing Motor and SwingB—Cover E—Housing H—Spring Stop Cushion ValveC—Cushion Valve Spool F—Plug (2 used)

The swing stop cushion valve (I) is fasten to the top ofswing motor (A). The Pst port line is connected, alongwith the swing brake release switch, to a tee fitting atthe S1 port of the dig pilot check valve block. The Pzulport line is connected to a tee at the P port of the dualsolenoid valve block.

The function of swing stop cushion valve is to releasethe pressure build up in the swing motor work circuit

cause by the inertia of the upperstructure after thepressure becomes less than the swing crossover reliefvalves pressure setting. The release of the pressure bythe cushion valve after the swing crossover relief valvecloses is to achieve a cushioned stop and to preventthe back and forth movement of the upperstructure.


PN=429


Theory Of Operation

90250542

TX,9025,GG1030 –19–09SEP97–2/6

TRAPPED OILP

PILOT OILQ

RETURN OILRCUSHION VALVESPOOLE

SPRINGH

SPRINGM

ORIFICEG

SHUTTLEVALVE

I

ACCUMULATORF

PZULPORT

BWORKCIRCUITK1.2 mm

ORIFICEO

RETURNPORTJ0.8 mm

ORIFICEN

WORKCIRCUITL

SPRINGC PILOT PRESSURESPOOL

D PST PORTA

SWING STOP CUSHION VALVE — NEUTRALST8412BA CV

T84

12B

A–1

9–02

SE

P97


PN=430


Theory Of Operation

90250543

TX,9025,GG1030 –19–09SEP97–3/6

SWING STOP CUSHION VALVE — NEUTRAL

D

B

S

A

F

H

JKL

M

I

N

O

C

G

E

TRAPPED OILP

PILOT OILQ

RETURN OILR

T8413AB CV

T84

13A

B–1

9–02

SE

P97

A—Pst Port G—Orifice K—Swing Motor Work Circuit P—Trapped OilB—Pzul Port H—Spring L—Swing Motor Work Circuit Q—Pilot OilC—Spring I—Shuttle Valve M—Spring R—Return OilD—Pilot Pressure Spool J—Return Port to Swing Motor N—0.8 mm Orifice S—Swing Stop CushionE—Cushion Valve Spool Case O—1.2 mm Orifice Valve—NeutralF—Accumulator

NOTE: Colored lines in art represent internalpassages in the housing.

NeutralThe oil in the swing motor work circuits (K and L) istrapped by the swing valve section spool and the

cushion valve spool (E). The swing motor ishydraulically “locked.”

Pilot oil (Q) from the P port of the dual solenoid valveblock to the Pzul port (B) is blocked by the pilotpressure spool (D).



PN=431

Theory Of Operation

90250544

TX,9025,GG1030 –19–09SEP97–4/6

SUPPLY OILP

PILOT OILQ

RETURN OILR

SWING STOP CUSHION VALVEACCELERATION PHASE

D

B

S

A

F

H

JKL

M

I

N

O

C

G

E

T8413AC CV

T84

13A

C–1

9–02

SE

P97

A—Pst Port G—Orifice K—Swing Motor Work Circuit P—Supply OilB—Pzul Port H—Spring L—Swing Motor Work Circuit Q—Pilot OilC—Spring I—Shuttle Valve (2 used) M—Spring R—Return OilD—Pilot Pressure Spool J—Return Port to Swing Motor N—0.8 mm Orifice S—Swing Stop CushionE—Cushion Valve Spool Case O—1.2 mm Orifice Valve—Acceleration PhaseF—Accumulator

Acceleration PhaseWhen swing function is actuated, pilot oil (Q) from S1port of dig pilot check valve block to the Pst port (A)pushes the pilot pressure spool (D) left against thespring (C). The pilot pressure spool shifts beforesupply oil (P) pressure in the swing motor work circuit(K or L) increases enough to move the upperstructure,

Pilot oil at the Pzul port (B) flows through the pilotpressure spool and pushes the cushion valve spool (E)

left against its spring (M). Some pilot oil also flowsthrough the orifice (G). At this time the orifice (G)remains open because spring (H) force plus pilot oilpressure is greater than the work circuit pressure.

The work circuits (K and L) in the cushion valve areblocked by the pilot pressure spool (D) and notconnected together at this time.



PN=432

Theory Of Operation

90250545

TX,9025,GG1030 –19–09SEP97–5/6

HIGH PRESSUREP

LOW PRESSUREQ

PILOT OILR

TRAPPED OILS

RETURN OILT

SWING STOP CUSHION VALVEBRAKING INITIAL PHASE

D

B

U

A

F

H

JKL

M

I

N

O

C

G

E

T8413AD CV

T84

13A

D–1

9–02

SE

P97

A—Pst Port G—Orifice L—Swing Motor Work Circuit R—Pilot OilB—Pzul Port H—Spring M—Spring S—Trapped OilC—Spring I—Shuttle Valve N—0.8 mm Orifice T—Return OilD—Pilot Pressure Spool J—Return Port to Swing Motor O—1.2 mm Orifice U—Swing Stop CushionE—Cushion Valve Spool Case P—High Pressure Valve—Braking InitialF—Accumulator K—Swing Motor Work Circuit Q—Low Pressure Phase

Braking Initial PhaseWhen the control lever is returned to neutral, thecontrol valve spool returns to its neutral positiontrapping oil in the work circuits (K and L) to start thebraking phase.

At the same time the Pst port (A) is open to returnthrough the pilot controller. The pilot pressure spool(D) is pushed right by its spring (C) stopping pilot oilflow through Pzul port (B). A passage is openedthrough the spool and the 0.8 mm orifice (N)connecting the work circuits together.

The high pressure (P) created in the work circuit (L) bythe inertia of the upperstructure pushes the shuttle

valve (I) against the spring (H) closing the orifice (G).The trapped oil (S) at the end of swing cushion valve(E) keeps the spool shifted to the left. The high workcircuit pressure also opens the swing crossover reliefvalve.

Oil flows through the crossover relief valve and 0.8mm orifice (N) releasing pressure to the other workcircuit. The crossover relief valve closes when thepressure decreases below its pressure setting. Oilcontinues to flow through the orifice decreasing thepressure in work circuit.


PN=433


Theory Of Operation

90250546

TX,9025,GG1030 –19–09SEP97–6/6

MEDIUMPRESSURE

P

LOW PRESSUREQ

PILOT OILR

DECREASINGPRESSURE

S

RETURN OILT

SWING STOP CUSHION VALVEBRAKING FINAL PHASE

D

B

U

A

F

H

JKL

M

I

N

O

C

G

E

T8413AE CV

T84

13A

E–1

9–02

SE

P97

A—Pst Port G—Orifice L—Swing Motor Work Circuit R—Pilot OilB—Pzul Port H—Spring M—Spring S—Decreasing PressureC—Spring I—Shuttle Valve N—0.8 mm Orifice T—Return OilD—Pilot Pressure Spool J—Return Port to Swing Motor O—1.2 mm Orifice U—Swing Stop CushionE—Cushion Valve Spool Case P—High Pressure Valve—Braking FinalF—Accumulator K—Swing Motor Work Circuit Q—Low Pressure Phase

Braking Final PhaseWhen the work circuit (L) pressure (P) decreasesbelow the oil pressure and spring (H) force at thespring end of shuttle valve (I), the valve is pushed leftopening the orifice (G). As the oil flows through theorifice decreasing the pressure (S), the cushion valvespool (E) is pushed right by its spring (M) to the centerposition.

At the center position an additional passage is openedthrough the 1.2 mm orifice (O) releasing work circuit

(L) pressure to the other work circuit (K) faster. Thefaster release of pressure prevents the back and forthmovement of upperstructure at the end of brakingphase.

As the oil pressure on the swing cushion valve spooldecrease the spool continues to move to the right.When the spool reaches its starting position, thepassages through the orifices (N and O) are closedand the swing motor becomes hydraulically “locked.”


PN=434

Theory Of Operation

90250547


PN=435

Theory Of Operation

90250548

TX,902505,SS572 –19–22SEP97–1/2

Swing Gearbox Operation

SWINGMOTOR

FIRSTSUN GEAR

BRAKECOOLINGPORT

BRAKERELEASEPORT

FIRSTPLANETCARRIER

FIRSTPLANETGEAR

TORETURN

SWINGBRAKE

RINGGEAR

SECONDSUN GEAR

SECONDPLANETGEAR

SECONDCARRIER

OUTPUTSHAFT

LOWERSEAL

SWINGGEAR

RPILOT OIL P

LUBRICATION OILSWING GEAR BOX QT6680AJ CV

H

M

L

K

I

J

B

C

A

G

F

E

D

O

N

T66

80A

J–1

9–22

SE

P97


PN=436


Theory Of Operation

TX,902505,SS572 –19–22SEP97–2/2

The swing gearbox (R) is a double planetary reductiongearbox. The output shaft of swing motor (H) is splinedto the first sun gear (I). A multiple wet disk swingbrake (F) is also splined to the first sun gear. Thisbrake is spring applied and hydraulically released.

The first sun gear turns the first planet gears (M) whichorbit inside of ring gear (E). As the planet gears orbitthe ring gear, the first planet carrier (L) turns. The firstplanet carrier turns the second sun gear (D).

The second planet works in the same manner as thefirst planet. Splined to the second planet carrier (B) isthe output shaft (A).

Oil from the pilot pump is routed to the swing brakecooling port (J). Most of the oil is used to cool theswing brake and lubricate the planetary in gearbox.

The tapered bearings on the output shaft (A) arelifetime lubricated. An oil seal is used to seal the cavityfor the bearings from the oil used to lubricate theplanetary.

90250549


PN=437

Theory Of Operation

TX,9025,LG36 –19–27AUG97–1/2

Control Valve And Manifold Operation—(Serial No. —556935)T110364 –19–28OCT97

The main hydraulic control valve (R) consists of acontrol valve manifold on which the individual valve

sections and the pressure control manifold aremounted.


PN=438

Theory Of Operation

90250551

TX,9025,LG36 –19–27AUG97–2/2

The work ports for the valve sections are identify bythe letters “A” and “B” on the housing. All “A” workports are to the front of the machine and all “B” workports are to the rear. The test ports (C and Q) in thepressure control manifold are identify by the letters “P”and “LS” stamped into the housing.

An orifice is located in each pressure equalizing(crossover) line from the left to right propel pilot caps.The orifices are “captured” in the connections ofcrossover hose end fitting to tee fitting at the rightpropel valve front and rear pilot caps. The orifice maybe and can be installed at either end of crossoverhoses.

A pilot check valve with orifice is used in the inlet portof pilot caps for swing and boom. (Serial No. —543989)A pilot check valve with orifice is also used inthe inlet port of pilot caps for the left and right propelvalve sections.

(Serial No. 543990—) Orifices are installed in the pilotline connections to the left and right propel valve pilotcaps. The orifices are “captured” in the connections ofpilot hose end fitting to tee fitting at the pilot caps.

No pilot check valves with orifices or orifices are usedfor the bucket and arm valve section pilot lines.

Swing Torque Control Valve (Serial No. 546277—)The swing torque control valve is located betweenswing valve and control valve manifold. (See SwingTorque Control Valve Operation in this group.)

Boom Regenerative Valve (Serial No. 545157—556935)

The boom regenerative valve is located between thecontrol valve manifold and boom valve section. Thevalve plate is installed so the letter “A” stamped on theplate is to the “A” end of boom valve. (See BoomRegenerative Valve Operation in this group.)

Arm Regenerative Valve (Serial No. 546277—556935)The arm regenerative valve is located between thecontrol valve manifold and arm valve section. The armcylinder restrictor (H) that was in the control valvemanifold is now located in the valve plate. Therestrictor serves the same function as before. (SeeArm Regenerative Valve Operation in this group.)

Arm Anti-Drift ValveThe arm anti-drift valve is mounted on the “B” (rear)work port of the arm valve section. The “B” work portis connected to the arm cylinder rod end circuit. Thevalve “X” port is connected to a tee fitting at the arm in(front) pilot cap. The “Y” port is connected to a teefitting at the reservoir. (See Anti-Drift Valve Operationin this group.)

Boom Anti-Drift ValveThe anti-drift valve in mounted on the “A” (front) workport of the boom valve section. The “A” work port isconnected to the boom cylinders head end circuit. Thevalve “X” port is connected to a tee fitting at the boomlower (rear) pilot cap. The “Y” port is connected to atee fitting at the reservoir. (See Anti-Drift ValveOperation in this group.)


PN=439

Theory Of Operation

TX,9025,DY6324 –19–16SEP97–1/1

Control Valve And Manifold Schematic (Serial No. —556935)

T8424BX CV

TRAPPED OIL

RETURN OIL

CONNECTION

PILOT OIL

SUPPLY OIL

LOAD SENSE OIL

ANTI CAVITATIONBACK PRESSURECHECK VALVE


TO HYDRAULICOIL COOLER

TO PUMPLOAD SENSEVALVE

FROM PROPEL PILOTCHECK VALVE BLOCK

FROM BUCKET, ARM,AND BOOM CONTROLVALVES

FROMPUMP 2

TOSWINGMOTOR

SWING

PILOT CHECKVALVE ANDORIFICE

ANTI CAVITATIONVALVE TO SWING

MOTOR

BOOM

"A""B""A""B"

LOADSENSESYSTEMRELIEFVALVE

SAFETYRELIEFVALVE

Z2

Z1

PILOTPRESSUREREGULATINGVALVE

COMBINEDFUNCTIONSHUTTLEVALVE

POWERBOOSTSOLENOID

ARM

"A""B"

BUCKET

CIRCUITRELIEF WITHANTI CAVITATION

ANTI CAVITATIONVALVE(MAKE UP VALVE)

TO LEFTMOTORPROPEL

OIL COOLERBYPASS

TO RIGHTPROPELMOTOR

RIGHTPROPEL

PILOT CAPCHECK VALVE

TO LEFTPROPELPILOT CAP

TO LEFTPROPELPILOT CAP

ORIFICE(2 USED)

FROMPUMP 1

LEFTPROPEL

TO RIGHTPROPELPILOT CAP

TO RIGHTPROPELPILOT CAP

PROPEL PILOTORIFICE (4 USED)(SN 543990 )

PROPEL PILOTCHECK VALVE ANDORIFICE (4 USED)(SN 543898)

T8424BX –19–02SEP97


PN=440

Theory Of Operation

90250553


PN=441

Theory Of Operation

TX,9025,LG38 –19–27AUG97–1/2

Boom, Swing, And Arm Control Valve Operation—(Serial No. 556936—)T110363 –19–28OCT97

The main hydraulic control valve (A) consists of acontrol valve manifold on which the individual valvesections are mounted.


PN=442

Theory Of Operation

90250555

TX,9025,LG38 –19–27AUG97–2/2

The work ports for the valve sections are identify bythe letters “A” and “B” on the housing. All “A“ workports are to the front of the machine and all “B” workports are to the rear. The test ports (B and C) in thepressure control manifold are identify by the letters “P”and “LS” stamped into the housing.

An orifice is located in each pressure equalizing(crossover) line from the left to right propel pilot caps.The orifices are “captured” in the connections ofcrossover hose end fitting to tee fitting at the rightpropel valve front and rear pilot caps. The orifice maybe and can be installed at either end of crossoverhoses.

A pilot check valve with orifice is used in the inlet portof pilot caps for swing and boom. A pilot check valvewith orifice is also used in the inlet port of pilot capsfor the left and right propel valve sections.

Orifices are installed in the pilot line connections to theleft and right propel valve pilot caps. The orifices are“captured“ in the connections of pilot hose end fitting totee fitting at the pilot caps.


Swing Torque Control ValveThe swing torque control valve is located betweenswing valve and control valve manifold. (See SwingTorque Control Valve Operation in this group.)

Arm Regenerative ValveThe arm regenerative valve (E) is located in the controlvalve manifold. The arm cylinder restrictor (D) is in thecontrol valve manifold. The restrictor serves the samefunction as before. (See Arm Regenerative ValveOperation in this group.)

Boom Cylinder RestrictorThe boom cylinder restrictor is located in the controlvalve manifold. (See Boom Cylinder RestrictorOperation in this group.)

Arm Anti-Drift ValveThe arm anti-drift valve is mounted on the “B” (rear)work port of the arm valve section. The “B” work portis connected to the arm cylinder rod end circuit. Thevalve “X” port is connected to a tee fitting at the arm in(front) pilot cap. The “Y” port is connected to a teefitting at the reservoir. (See Anti-Drift Valve Operationin this group.)

Boom Anti-Drift ValveThe anti-drift valve in mounted on the “A” (front) workport of the boom valve section. The “A” work port isconnected to the boom cylinders head end circuit. Thevalve “X” port is connected to a tee fitting at the boomlower (rear) pilot cap. The “Y” port is connected to atee fitting at the reservoir. (See Anti-Drift ValveOperation in this group.)


PN=443

Theory Of Operation

TX,9025,LG39 –19–27AUG97–1/1

Boom, Swing, And Arm Control Valve Schematic—(Serial No. 556936—)

A B

LSA Z2 Z1

BOOM

P

CHECKVALVE

SWING TORQUEPRESSUREREGULATINGVALVE

PILOT CAPCHECKVALVE

SWING VALVE

TOSWINGMOTOR

ANTICAVITATIONVALVE

PILOT CHECKVALVE ANDORIFICE

SWING TORQUECONTROL VALVE P2


ARMREGENERATIVEVALVE

ARMCYLINDERRESTRICTOR

TO PILOTFILTER OUTLET

ARMVALVE

PORT LINE

TO PROPEL, BUCKETCONTROL VALVELSA PORT LINE

TO DIGSHUTTLE VALVES1 PORT LINE

TO PROPELPILOT CHECKVALVE LINE

COMBINEDFUNCTIONSHUTTLE VALVE

FROM MAINHYDRAULIC PUMP

TO PROPEL, BUCKETCONTROL VALVEAND PUMP LSREGULATOR PORT LINE

ORIFICE

CHECK VALVE

TO PROPEL, BUCKETCONTROL VALVELEFT REARPORT LINE

BOOMCYLINDERRESTRICTOR

LOAD SENSESYSTEM RELIEFVALVE

POWER BOOSTSOLENOID VALVE

TTO HYDRAULICOIL TANK

ARM

A B

A

B

T110366

SUPPLY OIL

LOAD SENSE OIL

PILOT OIL

TRAPPED OIL

RETURN OIL

CONNECTION

CIRCUIT RELIEFAND ANTICAVITATIONVALVE

BOOMVALVE

CONTROL VALVE MANIFOLD OPERATION (SERIAL NO. 556936 —)

T110366 –19–28OCT97


PN=444

Theory Of Operation

90250557

TX,9025,GG1245 –19–09SEP97–1/1

Swing And Swing Torque Control Valves Schematic

SUPPLY OIL

LOAD SENSE OIL

PILOT OIL

TRAPPED OIL

RETURN OIL

CONNECTION

CHECK VALVE

CONTROL VALVEMANIFOLD

SPOOL


PILOTCHECK VALVEAND ORIFICE

TO SWINGMOTORANTI CAVITATION

VALVE

SWINGVALVE

SWING TORQUECONTROL VALVE

PRESSUREREGULATINGVALVE

T8425AC CV

T84

25A

C–1

9–02

SE

P97

NOTE: (Serial No. —546276) Long front machinesuse an earlier design swing torque controlvalve. (See Swing Torque Control Valve ForLong Front Machine (Serial No. —546276) inthis group.)

(Serial No. 546277—) The long frontmachines use the later designed swing torquecontrol valve. (See Swing Torque ControlValve Operation in this group.)


PN=445

Theory Of Operation

90250558

TX,9025,GG1247 –19–09SEP97–1/1

Boom, Regenerative And Anti-Drift Valves Schematic

SUPPLY OIL

LOAD SENSE OIL

PILOT OIL

TRAPPED OIL

CONNECTION

RETURN OIL BOOMCYLINDER

"A""B"

BOOMREGENERATIVEVALVE PLATE

SPOOL

CONTROL VALVE MANIFOLD


BOOMVALVE

ORIFICE

(S.N. —556935)

(S.N. —556935)

(S.N. 556936 —)

ANTI-DRIFTVALVE

CIRCUIT RELIEFANDANTI-CAVITATIONVALVE

PILOT CHECKVALVE AND ORIFICE

"X" "Y"

T8426AA CV


T84

26A

A–1

9–02

SE

P97


PN=446

Theory Of Operation

90250559

TX,9025,GG1248 –19–09SEP97–1/1

Arm, Regenerative And Anti-Drift Valves Schematic

T8426AB CV

SPOOL"A""B"

"X""Y"

W ARM REGENERATIVE VALVE — ARM IN


CIRCUIT RELIEFAND ANTI CAVITATIONVALVE

PILOTCAPCHECKVALVE


ARMVALVE

CONTROL VALVEMANIFOLD

SUPPLY OIL

LOAD SENSE OIL

PILOT OIL

TRAPPED OIL

RETURN OIL

CONNECTION


(S.N. —556935)

(S.N. —556935)

(S.N. 556936 —)

T84

26A

B–1

9–02

SE

P97


PN=447

Theory Of Operation

90250560

TX,9025,LG41 –19–27AUG97–1/2

Control Valve Manifold Operation—(Serial No. —556935)

T111718 CONTROL VALVE MANIFOLD—(S.N. —556935)

SUPPLY OIL

RIGHTPROPEL

P

M

F

G

I

J

K

L

A

B

C

LOADSENSE OILN

RETURN OILOD

FROMPUMP 1

TO SWINGGEARBOX


ARMVALVE


AUXILIARYVALVEPLATE

ANTICAVITATIONCHECK VALVE

TO OILCOOLER

FROMPUMP 2

NOTUSED

TORESERVOIR

OIL COOLERBYPASS VALVE

E

H

T11

1718

–19–

28O

CT

97


PN=448


Theory Of Operation

9025TX,9025,LG41 –19–27AUG97–2/2

Individual valve sections and the pressure controlmanifold are mounted to the manifold.

Pump supply (M) from both hydraulic pump is routedto the center passage. Supply oil is then routed toeach valve on both sides of the manifold and to thepressure control manifold.

Each valve section has two load sense ports. Loadsense (work port) pressure is routed to the pressurecontrol manifold.

The return passages contain the anti-cavitation checkvalve (L) and the oil cooler bypass valve (D). Theanti-cavitation check valve keep a minimum amount ofpressure in the return circuit for make-up valve oranti-cavitation valve function.

The oil cooler bypass valve protects the cooler if flowthrough the cooler becomes restricted.

(Serial No. —546276)The arm cylinder restrictor (H) is located in themanifold. Restrictor prevents arm in hesitation byrestricting return flow from arm cylinder rod end.

(Serial No. 546277—)The arm cylinder restrictor is now located in the armregenerative valve. Restrictor prevents arm inhesitation by restricting return flow from arm cylinderrod end. (See Arm Regenerative Valve Operation(Serial No. 546277—) in this group.)

0561


PN=449

Theory Of Operation

TX,9025,LG42 –19–27AUG97–1/2

Control Valve Manifold Operation—(Serial No. 556936—)

10

6

7

11

8

16

27

28

22

23

24

25

11

6

21 SAFETYRELIEFVALVE

TO RETURNMANIFOLD

FROM BOOM, SWING, AND ARM CONTROL VALVE LSA PORT

FROMMAINHYDRAULICPUMP

FROM HYDRAULICPUMP

COMBINEDFUNCTION SHUTTLEVALVE SPOOLFROM HYDRAULIC PUMP

TO PUMP REGULATORLS PORT

FROM BOOM, SWING, AND ARM CONTROL VALVE MANIFOLD LS PORT

TO RIGHTPROPELMOTORS

TO LEFTPROPELMOTORS

TOBUCKET

29 CONTROL VALVE MANIFOLD—(SERIAL NO. 556936— ) 30

26

PROPEL, BUCKET CONTROL VALVE

PILOT PRESSUREREGULATING VALVE

TO SWING TORQUECONTROL VALVE

TO ARMCONTROLVALVE

TO BOOMCONTROLVALVE


T2T


POWERBOOSTSOLENOID



LSA PORT

Z2 PORT

Z1 PORT

LS PORT

15

12

19

1

POWERBOOSTSOLENOID

5

10

18

T110873

SUPPLY OIL31

LOAD SENSE OIL32

RETURN OIL33

PILOT OIL34

1

FROMSWING VALVE

TOSWING VALVE

FROMSWING VALVE

10 TOPROPEL, BUCKETCONTROLVALVE

FROM MAINHYDRAULICPUMP

ARMVALVE

9

12

1315

14

11

6

87TOPUMPREGULATOR


5

4

LOADSENSESYSTEM RELIEFVALVE

FROMPILOTFILTER


BOOMVALVE

TOHYDRAULICOIL RETURNMANIFOLD

COMBINEDFUNCTIONSHUTTLEVALVE

16PILOTPRESSUREREGULATINGVALVE


22 3 20

T110873 –19–28OCT97


PN=450

Theory Of Operation

90250563

TX,9025,LG42 –19–27AUG97–2/2

Individual valve sections and the return manifold aremounted to the control valve manifold.

Pump supply oil (31) is routed to the center passage.Supply oil is then routed to each valve on both sides ofthe manifold and to the propel and bucket control valve“P” port (10).

Each valve section has two load sense ports. Loadsense (work port) pressure is routed to the pressureregulator (7).

The control valve manifold contains the pilot pressureregulating valve (16), load sense system relief valve(5), power boost solenoid (1), arm regenerative valve(11) and combined function shuttle valve (15).

Pilot oil (34) from pilot filter (4) is routed to the pilotpressure regulating valve (16). The pressure regulatingvalve limits the maximum allowable pilot pressure inthe circuit. Pilot oil is also routed to the power boostsolenoid (1). When activated by pressing the switch onthe top right pilot controller lever, the power boost

solenoid routes pilot oil to the spring side of the loadsense system relief valve (5). When deactivated, thepower boost solenoid routes the oil on the spring sideof the system relief valve to return.

Pump supply oil (31) from the control valve manifold(29) is routed to the safety relief valve in the propeland bucket control valve (30). The safety relief valveprotects the hydraulic system. When pressure exceedsthe spring force plus load sense (32) pressure, therelief valve opens, dumping the pressure spike toreturn.

Load sense oil from the control valve manifold isrouted to the load sense system relief valve (5). Thesystem relief valve limits the maximum systempressure by monitoring load sense pressure (work portpressure). Load sense oil is also routed to LS and LSAports and pump regulator (7).

The combined function shuttle valve (15) is used toimprove propel metering during combined functionoperation.


PN=451

Theory Of Operation

90250564

TX,9025,LG43 –19–27AUG97–1/2

Arm Cylinder Restrictor Operation

T75

70A

G–U

N–1

3AU

G91

(Serial No. —556935)



PN=452

Theory Of Operation

90250565

TX,9025,LG43 –19–27AUG97–2/2

T11

0442

–UN

–08S

EP

97

(Serial No. 556936—)

The arm cylinder restrictor screw (A) is used to restrictreturn oil flow from arm cylinder rod end. Restrictingcylinder rod end return flow eliminates movementhesitation when the arm is straight down.

With the boom raised and arm extended (cylinderretracted), gravity pulls the arm down faster than thepump can supply oil to the head end of cylinder whenarming in. When this happens, there is cavitation in thehead end of arm cylinder. To prevent cavitation, armcylinder restrictor adjusting screw is turned IN justenough to eliminate hesitation.

(Serial No. —546276)The arm cylinder restrictor is located on the rear of themain control valve manifold, in line with the arm valve.

(Serial No. 546277—)The arm cylinder restrictor (A) is now located in thearm regenerative valve. The restrictor serves the samefunction as before. See Arm Regenerative ValveOperation (Serial No. 546277—) in this group.

(Serial No. 556936—)The arm cylinder restrictor (A) is located in the controlvalve manifold.


PN=453

Theory Of Operation

90250566

TX,9025,LG44 –19–09SEP97–1/1

Boom Cylinder Restrictor Operation—(Serial No. 556936—)

T11

0443

–UN

–08S

EP

97

The boom cylinder restrictor screw (A) is used torestrict return oil flow from the boom cylinder headend. Restricting cylinder head end return floweliminates rapid downward movement.

When lowering the boom, gravity pulls the boom downfaster than the pump can supply oil to the rod end of

cylinder. When this happens, there is cavitation in therod end of the boom cylinder. To prevent cavitation,boom cylinder restrictor adjusting screw is turned INjust enough to eliminate cavitation.


PN=454

Theory Of Operation

90250567


PN=455

Theory Of Operation

90250568

TX,9025,JV264 –19–27AUG97–1/2

Control Valve Sections Operation

T8427AC CV

SHUTTLE VALVE

BALANCE VALVE

CIRCUIT RELIEFWITH ANTI CAVITATIONVALVE

SPOOL TRAVELSTOP SCREW

PILOT CAP

SPRING

POPPET

BALANCE VALVE

SPOOL

MAKE UP VALVEPILOT CAPCHECK VALVE

CENTERING SPRING

SUPPLY OILS

T

STEEL BALL

BALANCE VALVEPILOT CHECKVALVE

MAKE UP VALVE

UR SWING VALVE

O PROPEL VALVES

G BOOM, ARM, AND BUCKET VALVES

PILOT CHECKVALVE BOOM

CONTROL VALVE SECTIONSV

TRAPPED OIL

H

N

H

E

F

B

J

K

L

M

P

Q

D

C

I

PILOT CHECKVALVE(SN 543989)

A

A

A

RETURN OIL

T84

27A

C–1

9–02

SE

P97


PN=456


Theory Of Operation

90250569

TX,9025,JV264 –19–27AUG97–2/2

All control valve sections are pilot actuated, closedcenter. Centering springs (N) on both ends of thespool hold the spool in neutral when not actuated.

Each spool pilot cap contains a spool travel stop screw(F). The screws are adjustable to control functionspeed. They can also be turned IN to manually movethe spool and lower a function if the engine or pumpwill not operate.

A pilot check valve with orifice (A) is used in the inletport of pilot caps for swing and boom. (Serial No. —543989)A pilot check valve with orifice (A) is also usedin the inlet port of pilot caps for the left and right propelvalve sections. The check valves open allowing pilot oilto enter the caps quickly. Check valves close to restrictreturn flow through the orifices, allowing the controlvalve spool to move slowly for more control of thefunction.

(Serial No. 543990—) Orifices are installed in the pilotline connections to the left and right propel valve pilotcaps. The orifices are “captured” in the connections ofpilot hose end fitting to tee fitting at the pilot caps. Theorifices restrict flow in both direction for more control ofthe propel function.


A pilot cap check valve (air bleed) (I) is locatedbetween the pilot cap and return circuit. Wheneverpilot oil enters the pilot cap the ball moves off its seatand flushes a small amount of oil out of the pilot cap toreturn. Any air in the cap is automatically flushed outof the cap to return. The check valve on the other endis seated by return pressure.

Valve sections are similar in design with fewdifferences. Each valve spool has notches near end ofspool. Notches must always be towards the rod end“B” of the cylinder.

Boom, arm, and bucket valve sections (G) containcircuit relief valves with anti-cavitation valves (B).Control valve spools have two balance valves (D) andtwo shuttle valves (C).

Propel sections (O) contain make-up valves (H).Control valve spools have two balance valves (M) andtwo poppets (K) with springs (J).

Swing section (R) contains make-up valves. Controlvalve spool has two balance valves (Q) and two steelballs (P).


PN=457

Theory Of Operation

90250570

TX,902505,JV266 –19–09SEP97–1/2

Boom, Arm And Bucket Control Valve Operation—Neutral

SUPPLY OIL

TRAPPED OIL

RETURN OIL

RETURN

PUMP SUPPLY

RETURN

LOAD SENSE

CONTROL VALVE NEUTRAL

WORKPORT

WORKPORT

D

H

I

L

K

F

M

N

O

P

SPOOL

SHUTTLEVALVE

LOADSENSE

BALANCEVALVE

BALANCE VALVE

SHUTTLE VALVE

A

B

C

E

G

J

PILOTCAP CHECKVALVE

)(

)(

)()(

)(

)(

T7571AO CVCVCV

T75

71A

O–1

9–02

SE

P97


PN=458


Theory Of Operation

9025TX,902505,JV266 –19–09SEP97–2/2

NOTE: For swing control valve, see Swing ControlValve Operation in this group. For propelcontrol valves, see Propel Control ValveOperation in Group 9020-05.

Boom, arm, and bucket control valves are loadcompensation design. Load compensation means thatall functions will continue to move, regardless of whatpressure the function is at, without further movementof control levers.

Load sense compensation is achieved by independentmovement of two balance valves (E and G) and twoshuttle valves (B and J) in each cylinder valve spool(boom, arm, and bucket).

Each work port (K and L) has a balance valve andshuttle valve. Each valve section also has two return

passages (D and H) and two load sense passages (Cand I). Each valve section has one pump supplypassage.

When control levers are not actuated, the control valvespools are held in neutral by centering springs in thepilot caps. Pump supply passage (F) is blocked(closed center). In neutral pump supply, work port,return and load sense passages are all blocked by thespool (A). Oil in the work ports is trapped.

NOTE: For regenerative valves, anti-drift valves, andswing torque control valve see operationstories in this group.

0571


PN=459

Theory Of Operation

90250572

TX,902505,JV278 –19–09SEP97–1/2

Boom, Arm And Bucket Control Valve Operation—Starting To Move

T7571AP CV

SUPPLY OIL

CONTROL VALVE (STARTING TO MOVE)S

WORK PORT OIL

LOAD SENSE OIL

PILOT OIL

RETURN OIL

N

O

P

Q

R

SHUTTLEVALVE

SHUTTLEVALVE

PASSAGE "B"

PASSAGE "A"

PASSAGE "C"LS

R

WP

VENT

PASSAGE "D"P

WP

R

LS

PASSAGE "E"

VENT

PASSAGE "F"

BALANCEVALVE

SPOOL

BALANCEVALVE

A

B

C

D

E

F

G

H

I

J

K

L

M

T75

71A

P–1

9–02

SE

P97


PN=460


Theory Of Operation

9025TX,902505,JV278 –19–09SEP97–2/2

Whenever a pilot controller is moved, pilot oil (Q) isrouted to a control valve pilot cap. Pilot oil will start tomove the spool against the centering spring on theopposite end of the spool.

Load sensing “LS” is the first port to open. The secondport to open is work port “WP”. The upper work portwill be opened to return pressure due to the vent (E) inthe control spool passing over the return port. Theupper balance valve (J) and shuttle valve (A) will moveup to open all passages in the upper balance valve toreturn.

At this time the lower work port is at a higher pressurethan pump supply oil (N). Passage “D” (F) in the lowerbalance valve (L) will be open and force the lowershuttle valve (M) down. This will open passage “F” (I)and let work port oil flow behind the lower balancevalve and hold it shut until pump supply pressure ishigher than work port pressure. This will open the

passage between pump supply oil (N) and the workport. The balance valve in this mode is the lift checkvalve.

The pump supply port in control spool (K) is the lastport to open. When it opens, pump supply pressureflows through passage “E” (G) to the load sensepassage. The load sense pressure increases causingthe pump to increase swash, increasing pump supplypressure. The lower balance valve keeps the work portpassage closed until pump supply pressure is higherthan work port pressure. Once pump supply pressureis higher, the lower shuttle valve moves up connectingload sense pressure to passage “F”. The lowerbalance valve moves down allowing pump supplypressure to flow to the work port. With the balancevalve open, the cavity above the balance valveassumes approximate work port pressure. Thispressure flows through passage “E” allowing work portpressure to control load sense pressure.

0573


PN=461

Theory Of Operation

90250574

TX,902505,JV280 –19–09SEP97–1/2

Boom, Arm And Bucket Control Valve Operation—Full Actuation

) (

) (

) (

) (

SUPPLY OIL

WORK PORT OIL

LOAD SENSE OIL

PILOT OIL

RETURN OIL

SHUTTLE VALVE

SHUTTLE VALVE

VENT

BALANCE VALVE

BALANCE VALVE

LS

LS

R

R

WP

WP

P

SPOOL

A

B

C

D

E

F

G

H

I

J

K

CONTROL VALVE (FULL ACTUATION)T7571AQ LCV

T75

71A

Q–1

9–02

SE

P97


PN=462


Theory Of Operation

TX,902505,JV280 –19–09SEP97–2/2

The control spool (D) moves further as pilot pressure(J) increases. The return side of control valve willremain the same.

The control spool has moved up and pump supply “P”and work port “WP” are both open. Pump supplypressure is higher than work port because the balancevalve (E) is open. In single function operation, both thebalance valve and the shuttle valve are moved to thebottom of their bores.

The load sense pressure is always lower than pumpsupply pressure. Two factors establish the pressuredifference, load sense valve, and the orifice effect of

passages in the control valve between pump supplyport and work port. Supply oil must flow through threeopenings to get to work port. Every time the oil flowsthrough a passage there is a pressure drop, the sameway an orifice works. The smaller the opening, thesmaller the flow due to constant load sense pressure.An internal passage from work port to the load sensepassage routes pressure in this passage to the pumpregulator.

Load sense pressure is the same at both ends of allthe control spools because the two passages in thecontrol valve manifold are joined together in themanifold.

90250575


PN=463

Theory Of Operation

90250576

TX,902505,JV282 –19–09SEP97–1/2

Boom, Arm And Bucket Control Valve Operation—Combined

SUPPLY OIL

LS

R

WP

WP

P

LS

SPOOL

BALANCEVALVE

BALANCEVALVE

PASSAGE"A"

PASSAGE"B"

SHUTTLEVALVE

SHUTTLEVALVE

A

B

C

D

E

F

G

T7571AR CV

M VALVE "A" N VALVE "B"

HIGHEST WORKPORT PRESSURE

H

I

J

K

L

LOWEST WORKPORT PRESSUREPILOT OIL

RETURN OIL

WP

P

LS

R

WP

LS

CONTROL VALVE (COMBINED OPERATION)O

T75

71A

R–1

9–02

SE

P97


PN=464


Theory Of Operation

TX,902505,JV282 –19–09SEP97–2/2

Load compensation comes into effect whenever two ormore functions are actuated at the same time.

In this example, both control spools (A) are moved allthe way. Valve “A” (M) has a heavier load than valve“B” (N). Because of the heavier load, the work portpressure (I) in valve “A” is higher than in valve “B”.The load sense pressure is always the same as thehighest work port pressure. Therefore, pump supplypressure is higher than the highest work port pressure.

In conventional control spools, in this situation, valve“B” would receive all the oil and valve “A” would get

very little or no oil. Valve “A” balance valve (B) andshuttle valve (G) are both wide open. In valve “B”pump supply oil (H) is higher than lowest work portpressure (J). Pump supply oil flows through passage“A” (D) and shifts the shuttle valve (F) up shutting offwork port pressure. When the shuttle valve moves up,it opens passage “B” (E) from load sense to thebottom of balance valve (C). The pressure under thebalance valve will move the valve up and reduce theoil flow to that work port.

90250577


PN=465

Theory Of Operation

90250578

TX,902505,JV284 –19–09SEP97–1/2

Swing Control Valve Operation

T7577AC CV

SUPPLY OILO

P

Q

SWING CONTROL VALVE

TRAPPED OIL

RETURN OIL

R

TORETURN

BALANCESPOOL

PILOTCAP

BALL

LOADSENSE

FROMPUMP

TORETURN

LOADSENSE

BALANCESPOOL

BALL

NOTCH

SPOOL STOPSCREW

PILOT CAPRELIEF VALVE(AIR BLEED)

MAKE-UPVALVE

WORKPORT

WORKPORT

SPOOL

PILOT CHECK

G

H

I

J

A

B

C

D

E

F

C

D

EK

L

M

N

B

T75

77A

C–1

9–02

SE

P97


PN=466


Theory Of Operation

TX,902505,JV284 –19–09SEP97–2/2

The swing valve is the same design as boom, arm,and bucket control valves, except for three areas.Swing valve is a smaller capacity, like propel valves,than the cylinder valves. Swing valve uses make-upvalve, like propel, not anti-cavitation relief valves.Inside the swing valve, balance valve is a ball, not ashuttle valve.

The ball acts the same as a shuttle valve, except it isan ON—OFF valve that does not meter flow.

The balance valves act the same as the balancevalves in the cylinder valves.

90250579


PN=467

Theory Of Operation

90250580

TX,902505,SS648 –19–09SEP97–1/2

Circuit Relief And Anticavitation Valve Operation

T7585AI CV

RELIEF PRESSURE

SUPPLY OIL PRESSURE

LOW WORK PORT PRESSURE

RETURN OIL PRESSURE

COMBINED CIRCUIT RELIEF AND ANTI-CAVITATIONM

I

J

K

L

ADJUSTMENTSCREW

ORIFICE

RELIEF ANDANTI-CAVITATIONPOPPET

PISTON

PILOTPOPPET

G RELIEF OPERATION

H ANTI-CAVITATION OPERATION

F NORMAL OPERATION

B

A

C

D

E

T75

85A

I–1

9–02

SE

P97


PN=468


Theory Of Operation

9025TX,902505,SS648 –19–09SEP97–2/2

The boom, arm, and bucket control valve sectionshave circuit relief with anticavitation features.

During normal operation (F) oil pressure in the workcircuit is less than the circuit relief valve setting andthe circuit relief valve remains closed.

During relief operation (G), the relief valve will open inthree steps. In the first step, the pilot poppet (D) isopened. Flow restriction through the hollow piston (C)causes the pressure in the cavity behind the mainpoppet (B) to decrease. In the second step of reliefoperation, the piston seats against the poppet. Thisfurther reduces oil flow into the cavity and greatlydecreases the pressure against the back side of mainpoppet. Some oil still flows into the cavity through theclearance between the piston and the main poppet.The main poppet opens in the third step of reliefoperation.

When the relief valve again closes, the piston and pilotpoppet move together until the pilot poppet is seated.Oil flows into the cavity through the clearance betweenthe piston and main poppet to move the piston awayfrom the pilot poppet. This permits flow into the cavitythrough the piston to seat the main poppet.

During anticavitation operation (H) the main poppet willretract to allow oil to flow from the return passage intothe work circuit. During normal operation and reliefoperation oil pressure on surface held the main poppetagainst its seat. This pressure decreases as pressurein the work circuit decreases. The return oil pressureon the surface moves the main poppet and pistonagainst the springs to open the valve.

0581


PN=469

Theory Of Operation

90250582

TX,902505,SS650 –19–09SEP97–1/1

Make-Up Valve Operation

T7585AJ CV

SUPPLY OIL

LOW PRESSURE OIL

RETURN OILMAKE UP VALVE

G

H

IJ

MAKE UP OPERATION

NORMAL OPERATION

SPRING POPPET

RETURN

DWORK PORT

E

FA B

C

T75

85A

J–1

9–02

SE

P97

Located on the swing, left propel, and right propelcontrol valve sections are make-up valves (J). Themake-up valves supply the motors with oil to preventcavitation.

In normal operation (E) work port pressure (D) will besensed on the face of poppet (B). Also work port

pressure will pass through the poppet and along withspring force will hold the poppet on the seat.

Whenever work port pressure drops below returnpressure, return pressure will open the poppet andreturn oil (I) will flow into the work port.


PN=470

Theory Of Operation

90250583


PN=471

Theory Of Operation

90250584

TX,9025,LG47 –19–27AUG97–1/2

Return Manifold Operation (Serial No. 556936—)

HIGH PRESSURE RETURN HYDRAULIC OIL

LOW PRESSURE RETURN HYDRAULIC OIL

O-RING

HOUSING

SPRING

TO BOOM,SWING, ARMCONTROL VALVE

R

T

DO

P

MN

A BO-RING

C

POPPETE

O-RING

HOUSING

TOOILCOOLER

SPRING

TO BOOM,SWING, ARMCONTROL VALVE

DO

P

MN

A BO-RING

CO-RING

O-RING

POPPET

GSEAL

F SPRINGH

L K

POPPETE

Q

RETURN OILST110390

I

VALVEJ

TOOILCOOLER

O-RING

O-RING

POPPET

GSEAL

F SPRINGH

L K

I

VALVEJ

TORESERVOIR

BYPASSRELIEFVALVE

RETURNMANIFOLDHOUSING

RETURN MANIFOLD

T11

0390

–19–

28O

CT

97


PN=472


Theory Of Operation

TX,9025,LG47 –19–27AUG97–2/2

A—O-Ring F—Seal K—Poppet P—To ReservoirB—Spring G—O-Ring L—Oil Cooler Outlet Q—High Pressure Return OilC—O-Ring H—Spring M—From Main Control Valve R—Low Pressure Return OilD—Housing I—O-Ring N—Return Manifold Housing S—Return OilE—Poppet J—Valve O—Bypass Relief Valve T—Return Manifold

The return manifold (T) is located on the rear of theboom, swing, and arm control valve manifold.

The return manifold receives return oil (S) from theboom, swing, and arm control valve and propel andbucket control valve.

The primary function of the return manifold is to routelow pressure return oil (R) to the oil cooler. Thesecondary function is to route high pressure return oil(Q) (common during cold starts) through an externallymounted bypass relief valve (O). Oil flows through thisvalve to the hydraulic oil reservoir.

90250585


PN=473

Theory Of Operation

90250586

TX,9025,LG48 –19–27AUG97–1/5

Boom Regenerative Valve Operation—(Serial No. 545157—556935)

T83

86A

C–1

9–02

FE

B94

A—Boom Valve C—Head End Return Passage G—Plug (2 used) J—Boom Regenerative ValveB—Circuit Relief and D—Pump Supply Passage H—Orifice with Boom Valve

Anti-Cavitation Valve (2 E—Rod End Return Passage I—Plateused) F—Load Sense Passage (2

used)

The boom regenerative valve plate (I) is locatedbetween the control valve manifold and boom valve(A). The plate is installed so the letter “A” stamped onthe plate is to the “A” end of boom valve.

An orifice (H) is located in the plate return passage onthe side against the manifold. The orifice and passageare aligned with the rod end return passage (E) ofboom valve at the “B” end.

The return passage at the “A” end of plate is closed onthe side against the manifold. Return oil from the head

end return passage (C) of boom valve cannot flowdirectly into the manifold but flows through a passagein the plate to the return passage at the other end.

NOTE: The letters “A” and “B” are located next to theboom valve work port.

The openings in the boom valve spool for boom downoil flow are smaller than the earlier design boom valve.The boom valve for early machines will not work withthe boom regenerative valve.


PN=474


Theory Of Operation

TX,9025,LG48 –19–27AUG97–2/5

The function of boom regenerative valve during boomdown is to route return oil from the head end of boomcylinders to its rod end through the regenerative valveplate and anti-cavitation valve. The regenerativefeature works when the weight of the boom on thecylinders is pushing the return oil out the head endsuch as when lowering the boom back into a trench.

The return oil combines with the pump supply oil andflows to the rod end of cylinders. The openings inboom valve spool for boom down flow can be smallerbecause the greater volume of oil to fill the rod end iscoming from the head end through the regenerativevalve and anti-cavitation valve and there is less needfor oil from the pump to fill the rod end.


90250587


PN=475

Theory Of Operation

90250588

TX,9025,LG48 –19–27AUG97–3/5

BOOMCYLINDER

CIRCUIT RELIEFANDANTI-CAVITATIONVALVE

BOOMVALVE

"B" "A"

B

L

C

K

E

F

H

F

D

A

SUPPLY OILM

LOAD SENSE OILN

PILOT OILO

REGENERATIVE OILP

RETURN OILQ

BOOM REGENERATIVE VALVE—BOOM DOWN (S.N. 545157—556935) RT111721

HEAD ENDRETURNPASSAGE

HEAD ENDRETURNPASSAGE

BOOMREGENERATIVEVALVE PLATE

PUMPSUPPLYPASSAGE

RETURN PASSAGE

C

DH ORIFICE

LOADSENSEPASSAGE

C

LOADSENSEPASSAGE

K

F

E

I

T11

1721

–19–

28O

CT

97


PN=476


Theory Of Operation

90250589

TX,9025,LG48 –19–27AUG97–4/5

A—Boom Valve E—Rod End Return Passage K—Return Passage P—Regenerative OilB—Circuit Relief and F—Load Sense Passage (2 L—Boom Cylinders Q—Return Oil

Anti-Cavitation Valve used) M—Supply Oil R—Boom RegenerativeC—Head End Return Passage H—Orifice N—Load Sense Oil Valve—Boom DownD—Pump Supply Passage I—Boom Regenerative Valve O—Pilot Oil

Plate

When boom down function is actuated, regenerative oil(P) flows from the head end of boom cylinders,through the boom valve head end return passage (C),and into the boom regenerative valve plate (I).Because the return passage to the manifold is blockedby the plate, the regenerative oil flows through thereturn passage (K) in the plate to the rod end returnpassage (E). The orifice (H) restricts the flow of oil intothe manifold increasing the pressure. The increasedpressure opens the anti-cavitation valve (B) allowing oilfrom the head end of boom cylinders to flow to the rodend. Excess return oil flows through the orifice and intomanifold return passage.

The pump supply oil not needed for boom downfunction because of the boom regenerative valve isavailable for other hydraulic function.

When cutting down the side of a bank or trench usingboom down, the smaller openings in the boom valvedoes not reduce pump supply oil flow to the rod end ofcylinders enough to affect machine performance. Loadsense and the balance valve in spool operate normallyto send pump supply oil to the rod end of boomcylinders forcing the boom down. The anti-cavitationvalve is held closed by the higher pressure in the workport so all return oil flows through the orifice and intothe manifold return passage.



PN=477

Theory Of Operation

90250590

TX,9025,LG48 –19–27AUG97–5/5

T8389AB CV

LOAD SENSE OILN

PILOT OILO

SUPPLY OILM

RETURN OILPBOOMCYLINDERS

"A""B"

L

C

D

K

E

H

F

BOOM REGENERATIVEVALVE PLATE

ROD END RETURNPASSAGE

HEAD ENDRETURN PASSAGE

RETURN PASSAGE

PUMP SUPPLY PASSAGE

ORIFICE

F LOAD SENSE PASSAGEI

R

BOOMVALVE

A

CIRCUIT RELIEFANDANTI-CAVITATIONVALVE B

BOOM REGENERATIVE VALVE — BOOM UP

T83

89A

B–1

9–02

SE

P97

A—Boom Valve E—Rod End Return Passage K—Return Passage O—Pilot OilB—Circuit Relief and F—Load Sense Passage (2 L—Boom Cylinders Q—Return Oil

Anti-Cavitation Valve used) M—Supply Oil R—Boom RegenerativeC—Head End Return Passage H—Orifice N—Load Sense Oil Valve—Boom UpD—Pump Supply Passage I—Boom Regenerative Valve

Plate

When boom up function is actuated the regenerativevalve has no effect on control valve operation exceptnow the return oil flows through the orifice in the plate.The boom up cycle time is not affected by the orifice.

The orifice size is large enough to allow the return oilfrom the rod end of boom cylinders to flow to returnand not slow down the boom up function.


PN=478

Theory Of Operation

90250591


PN=479

Theory Of Operation

90250592

TX,9025,LG49 –19–27AUG97–1/6

Arm Regenerative Valve Operation—(Serial No. 546277—556935)

T83

91A

N–1

9–02

FE

B94

A—Plug D—Arm Regenerative Valve G—Cover K—Load Sense PassageB—Arm Cylinder Restrictor Plate H—Head End Return Passage L—Arm ValveC—To Manifold Return E—Poppet I—Pump Supply Passage M—Arm Regenerative Valve

Passage F—Spring J—Rod End Return Passage

The arm regenerative valve plate (D) is installedbetween the control valve manifold and arm valve (L).The return passages through the valve plate areblocked so return oil from the arm cylinder cannot flowdirectly to the control valve manifold return passage

(C) but must flow past a poppet (E). The arm cylinderrestrictor (B) that was in the control valve manifold ismoved to the valve plate. The restrictor serves thesame function as before.


PN=480


Theory Of Operation

TX,9025,LG49 –19–27AUG97–2/6

The function of the arm regenerative valve is to routereturn oil from one end of the cylinder to the otherthrough the anti-cavitation valve. The regenerativefeature for arm function works in both directions. Thereturn oil combines with the pump supply oil to movethe cylinder. Because of the volume of return oiladded, the demand for pump supply oil is less. Pump

supply oil not needed to move the cylinder is availableto operate other hydraulic functions. Return oil is onlyrouted to the other end of cylinder when pressure isequal to or less than the pressure setting of poppet (E)and spring (F). Using the regenerative valve improvesthe control of arm when the weight of the arm movesthe cylinder faster than the pump can supply oil.


90250593


PN=481

Theory Of Operation

90250594

TX,9025,LG49 –19–27AUG97–3/6

T111722 CV

ARMREGENERATIVEVALVE PLATE

RETURNPASSAGE

W


ROD ENDRETURN PASSAGE

ARM CYLINDERRESTRICTOR

PLUG

LOADSENSEPASSAGE

K

ARM REGENERATIVE VALVE — ARM IN (S.N. 546277—556935)

E POPPET

CCONTROL VALVEMANIFOLD RETURNPASSAGE

G COVER

F SPRINGD

A

N HJB

ARMCYLINDER Q

SPOOL O

PUMP SUPPLYPASSAGE

CIRCUIT RELIEFAND ANTI-CAVITATIONVALVE

P

H

B

I

K

K

N

J

CF

L

D

E

SUPPLY OILR

LOAD SENSE OILS

PILOT OILT

REGENERATIVE OILU

RETURN OILV

"A""B"

T11

1722

–19–

28O

CT

97


PN=482


Theory Of Operation

9025TX,9025,LG49 –19–27AUG97–4/6

A—Plug F—Spring N—Return Passage S—Load Sense OilB—Arm Cylinder Restrictor G—Cover O—Spool T—Pilot OilC—To Manifold Return H—Head End Return Passage P—Circuit Relief and U—Regenerative Oil

Passage I—Pump Supply Passage Anti-Cavitation Valve V—Return OilD—Arm Regenerative Valve J—Rod End Return Passage Q—Arm Cylinder W—Arm Regenerative Valve—

Plate K—Load Sense Passage R—Supply Oil Arm InE—Poppet L—Arm Valve

When arm in function (W) is actuated with the arm fullyextended, regenerative oil (U) flow is from the cylinderrod end, through arm valve return passage (J), to thearm regenerative valve plate (D). The oil flow isrestricted by the arm cylinder restrictor (B) to controlthe retraction of the arm. Oil then flows through theplate return passage (N) to the poppet (E). Becausethe pressure at the cylinder head end is less than thepressure setting of poppet (E), regenerative oil flowpushes the head end anti-cavitation valve (P) open.

The regenerative oil flows through the anti-cavitationvalve combining with pump supply oil and then out tothe arm cylinder head end.

When the arm moves past the vertical position thepressure on the cylinder head end increases closingthe anti-cavitation valve. The oil pressure in the returnpassage increases pushing the poppet (E) open. Thereturn oil flows past the poppet to the manifold returnpassage (C).

0595



PN=483

Theory Of Operation

90250596

TX,9025,LG49 –19–27AUG97–5/6

T111723

ARMREGENERATIVEVALVE PLATE

RETURNPASSAGE

W


ROD ENDRETURN PASSAGE

ARM CYLINDERRESTRICTOR

PLUG

LOADSENSEPASSAGE

K

ARM REGENERATIVE VALVE—ARM OUT (S.N. 546277—556935)

E POPPET

CCONTROL VALVEMANIFOLD RETURNPASSAGE

G COVER

F SPRINGD

A

N HJB

SUPPLY OILR

LOAD SENSE OILS

PILOT OILT

RETURN OILUARMCYLINDER

Q

SPOOLO

CIRCUIT RELIEF ANDANTI-CAVITATIONVALVE

P

H

B

I

K

N

J

K

CF

L

D

E

"A""B"

T11

1723

–19–

28O

CT

97


PN=484


Theory Of Operation

TX,9025,LG49 –19–27AUG97–6/6

A—Plug F—Spring L—Arm Valve R—Supply OilB—Arm Cylinder Restrictor G—Cover N—Return Passage S—Load Sense OilC—To Manifold Return H—Head End Return Passage O—Spool T—Pilot Oil

Passage I—Pump Supply Passage P—Circuit Relief and V—Return OilD—Arm Regenerative Valve J—Rod End Return Passage Anti-Cavitation Valve W—Arm Regenerative Valve—

Plate K—Load Sense Passage Q—Arm Cylinder Arm OutE—Poppet

For arm out function from the fully retract position tothe vertical position, regenerative oil flow is from thecylinder head end, through arm valve head end returnpassage (H) and into the arm regenerative valve plate(D). The regenerative oil flows through plate returnpassage (N), past the arm cylinder restrictor (B), intothe rod end return passage (J), pushes the rod endanti-cavitation valve (P) open and flows out to thecylinder rod end.

As the arm moves past the vertical position thepressure on the cylinder rod end increases closing theanti-cavitation valve. The oil pressure in the returnpassage increases pushing the poppet (E) open. Thereturn oil flows past the poppet to the manifold returnpassage (C).

90250597


PN=485

Theory Of Operation

90250598


PN=486

Theory Of Operation

90250599

TX,9025,LG50 –19–23OCT97–1/5

Arm Regenerative Valve Operation—(Serial No. 556936—)

T11

0399

–19–

28O

CT

97

A—Cover C—Poppet E—Control Valve Manifold G—Arm Cylinder RestrictorB—Spring D—Arm Regenerative Valve F—Arm Valve H—Boom Valve

The arm regenerative valve (D) is installed on the rightside of the control valve manifold (E) and above theboom valve (H). The return passages through thevalve plate are blocked so return oil from the armcylinder cannot flow directly to the control valvemanifold return passage but must flow past a poppet(C). The arm cylinder restrictor (G) is in the controlvalve manifold. The restrictor serves the same functionas before.

The function of the arm regenerative valve is to routereturn oil from one end of the cylinder to the other

through the anti-cavitation valve. The regenerativefeature for arm function works in both directions. Thereturn oil combines with the pump supply oil to movethe cylinder. Because of the volume of return oiladded, the demand for pump supply oil is less. Pumpsupply oil not needed to move the cylinder is availableto operate other hydraulic functions. Return oil is onlyrouted to the other end of cylinder when pressure isequal to or less than the pressure setting of poppet (C)and spring (B). Using the regenerative valve improvesthe control of arm when the weight of the arm movesthe cylinder faster than the pump can supply oil.



PN=487

Theory Of Operation

902505

,100

TX,9025,LG50 –19–23OCT97–2/5

T110400 CV H ARM REGENERATIVE VALVE — ARM IN

ARMCYLINDER C

SPOOL D

PUMP SUPPLYPASSAGE

CIRCUIT RELIEFAND ANTI-CAVITATIONVALVE

E

M

L

J

G

G

K

F

B

A

SUPPLY OILN

LOAD SENSE OILO

PILOT OILP

REGENERATIVE OILQ

RETURN OILR

"A""B"

I

H

T11

0400

–19–

28O

CT

97

A—Control Valve Manifold F—Rod End Return Passage J—Pump Supply Passage O—Load Sense OilB—Arm Valve G—Load Sense Passage K—Return Passage P—Pilot OilC—Arm Cylinder H—Arm Regenerative Valve— L—Arm Cylinder Restrictor Q—Regenerative OilD—Spool Arm In M—Head End Return Passage R—Return OilE—Circuit Relief and I—To Manifold Return Passage N—Supply Oil

Anti-Cavitation Valve


PN=488


Theory Of Operation

TX,9025,LG50 –19–23OCT97–3/5

When arm in function (S) is actuated with the arm fullyextended, regenerative oil (Q) flow is from the cylinderrod end, through rod end return passage (F), to thecontrol valve manifold (A). The oil flow is restricted bythe arm cylinder restrictor (L) to control the retractionof the arm. Oil then flows through the control manifoldpassage (K) to the arm regenerative valve (H) and thehead end circuit relief and anti-cavitation valve (E).Because the pressure at the cylinder head end is lessthan the pressure setting of the arm regenerative valve(H), regenerative oil flow pushes the head end

anti-cavitation valve open. The regenerative oil flowsthrough the anti-cavitation valve combining with pumpsupply oil and then out to the arm cylinder head end.

When the arm moves past the vertical position thepressure on the cylinder head end increases closingthe anti-cavitation valve. The oil pressure in the returnpassage increases pushing the arm regenerative valve(H) open. The return oil flows past the armregenerative valve (H) to the manifold return passage(I).

902505,101



PN=489

Theory Of Operation

902505

,102

TX,9025,LG50 –19–23OCT97–4/5

T110401 CV K ARM REGENERATIVE VALVE — ARM OUT

SUPPLY OILN

LOAD SENSE OILO

PILOT OILP

RETURN OILQ

ARMCYLINDER

C

SPOOLD

CIRCUIT RELIEF ANDANTI-CAVITATIONVALVE

B

F

H

L

G

I

E

G

J

A

M

"A""B"

K

T11

0401

–19–

28O

CT

97

A—Arm Valve E—Rod End Return Passage J—To Manifold Return M—Control Manifold ValveB—Circuit Relief and F—Head End Return Passage Passage N—Supply Oil

Anti-Cavitation Valve G—Load Sense Passage K—Arm Regenerative Valve— O—Load Sense OilC—Arm Cylinder H—Arm Cylinder Restrictor Arm Out P—Pilot OilD—Spool I—Return Passage L—Pump Supply Passage Q—Return Oil

For arm out function from the fully retract position tothe vertical position, regenerative oil flow is from thecylinder head end, through arm valve head end returnpassage (F) and into the control valve manifold (M).

The regenerative oil flows through the return passage(I), past the arm cylinder restrictor (H), into the rod endreturn passage (E), pushes the rod end anti-cavitationvalve (B) open and flows out to the cylinder rod end.


PN=490


Theory Of Operation

TX,9025,LG50 –19–23OCT97–5/5

As the arm moves past the vertical position thepressure on the cylinder rod end increases closing theanti-cavitation valve. The oil pressure in the returnpassage increases pushing the arm regenerative valve

(K) open. The return oil flows past the armregenerative valve (K) to the manifold return passage(J).

902505,103


PN=491

Theory Of Operation

902505

,104

TX,9025,GG1239 –19–09SEP97–1/4

Anti-Drift Valves For Arm And Boom Operation

LOW PRESSURE

T111920 CV

M

TRAPPED OILN

RETURN OILO

L

A

B I C E

D

H

G

K

F

L

K J I H G F

A B EC D"X" PORT "Y" PORT ORIFICE CHECK VALVE TO CYLINDER

FROMCONTROL VALVE

TO RELIEFVALVE

POPPETPISTON PILOTPOPPET

RELIEFVALVE

ANTI-DRIFT VALVE — CLOSED

TO "Y"PORT

P

T11

1920

–19–

28O

CT

97


PN=492


Theory Of Operation

902505,105

TX,9025,GG1239 –19–09SEP97–2/4

A—“X” Port (Pilot Pressure) E—To Cylinder I—Pilot Poppet M—Medium PressureB—“Y” Port (Return) F—From Control Valve J—Piston N—Trapped OilC—Orifice G—To Relief Valve K—Relief Valve O—Return OilD—Check Valve H—Poppet L—To “Y” Port P—Anti-Drift Valve—Closed

The function of anti-drift valve (P) is to prevent cylinderdrift by stopping leakage from the cylinder backthrough the control valve section.

One anti-drift valve is mounted on the rear work port ofarm valve section for the rod end circuit and one onthe front work port of boom valve section for the headend circuit. For the arm anti-drift valve, the “X” port (A)for pilot oil pressure is connected to a tee fitting at thefront pilot cap. For the boom anti-drift valve, the “X”port (A) for pilot oil pressure is connected to a teefitting at the rear pilot cap. The “Y” port (B) isconnected to a tee fitting at the reservoir and is usedfor return oil (O) from the spring cavities of theanti-drift and relief valves

When function is not actuated, the pressure (M)generated in the circuit to the cylinder (E) by the loadis sense at the spring side of poppet (H) through the

orifice (C). The oil to fill the poppet spring cavity flowsthrough the small clearance between the poppet landand housing and then through the orifice. The pressurein the spring cavity and the spring hold the poppetagainst its seat making a leak-free circuit. The checkvalves (D) are also held closed by the pressure.

The anti-drift valve isolates the cylinder circuit from thecircuit relief valve in the control valve section. Aparallel-connected direct-acting relief valve (K) protectsthe cylinder circuit from the pressure peaks andshocks which can occur when the control valve isclosed. The passage to relief valve (G) routes thepressure oil to the relief valve. The relief valve relievesinto the passage from control valve (F). The circuitrelief valve then relieves the pressure peaks andshocks to the return circuit in the control valve. Therelief valve (K) spring cavity is open to return through apassage to “Y” port (L).



PN=493

Theory Of Operation

902505

,106

TX,9025,GG1239 –19–09SEP97–3/4

PILOT OIL

T111921 CV

N

RETURN OILO

"X"PORT

"Y"PORT

ORIFICE CHECK VALVE

TO CYLINDER

FROMCONTROL VALVE

TO RELIEFVALVE

POPPETPISTON

PILOTPOPPET

RELIEFVALVE

J

K IH

G

B

A

L

F

K

G

H

D

ECI

F

E

DCBA

ANTI-DRIFT VALVE — OPENP

T11

1921

–19–

28O

CT

97

A—“X” Port (Pilot Pressure) E—To Cylinder I—Pilot Poppet N—Pilot OilB—“Y” Port (Return) F—From Control Valve J—Piston O—Return OilC—Orifice G—To Relief Valve K—Relief Valve P—Anti-Drift Valve—OpenD—Check Valve H—Poppet L—To “Y” Port


PN=494


Theory Of Operation

9025TX,9025,GG1239 –19–09SEP97–4/4

When the boom down or arm out function is actuated,pilot oil (N) also flows to the anti-drift valve “X” port(A). The pilot oil pushes the piston (J) against the pilotpoppet (I) pushing it off its seat. Oil then flows from thepoppet (H) spring cavity, past the pilot poppet and outthe “Y” port (B) faster than oil can flow through theorifice (C) causing the pressure in the cavity todecrease. Return oil (O) from the cylinder (E) pushesthe poppet off its seat opening the passage to thecontrol valve (F) for the normal free-flow of oil to thereturn circuit. The poppet is pushed open by the returnoil because the OD at poppet land is slightly largerthan the OD at the head end of poppet.

When the control lever is returned to neutral, the pilotcap and anti-drift valve “X” port (B) are open to returnthrough the pilot controller. The control valve spool isreturned to its neutral position by its centering spring.The oil in the circuit to cylinder is again trappedcausing the pressure in the circuit to increase withrespect to the load on the cylinder. As the pilot oil

pressure at the “X” port decreases below the pistonand pilot poppet spring force, the pilot poppet closesstopping the flow of return oil out the “Y” port. Oil flowsacross the poppet land and then through the orifice (C)increasing the pressure in the poppet (G) spring cavity.The poppet closes with a deliberate delay action so itdoes not override the normal closing action of thecontrol valve spool.

For boom down or arm in function, the anti-drift valveacts as a lift check. As the pressure oil from controlvalve (F) increases and pushes on the head end ofpoppet the pressure in the poppet (H) spring cavityalso increases. When the spring cavity pressurebecomes greater than the load (pressure) on thecylinder, the check valves (D) opens releasing thepressure in the spring cavity. Pressure oil from thecontrol valve pushes the poppet open opening thepassage from control valve to the cylinder for thenormal flow of oil to move the cylinder.

05,107


PN=495

Theory Of Operation

902505

,108

TX,9025,GG1250 –19–09SEP97–1/3

Swing Torque Control Valve OperationFor Long Front Machines—(Serial No. —546276)

T7678AB CV

SHUTTLEVALVE

LS FROMSWINGCONTROLMANIFOLD

RELIEFVALVE

SPRING

POPPET

ORIFICE


SHIMS

SPRING

FROMPILOTCAP

LSFROMMANIFOLD

FROMSWINGVALVEPILOTCAP

BALL

CHECKVALVE

SPOOL

SHUTTLESPOOL

ORIFICE

SPRING

SWING TORQUE CONTROL PLATE

SUPPLY OIL

PILOT OIL

LOAD SENSE OIL

RETURN OIL

MULTIPLE FUNCTIONS

X

I

J

H

G

F

E

N

O

S

M

L

AQ

R

B

C

D

P

T

U

V

W

K

T76

78A

B–1

9–02

SE

P97


PN=496


Theory Of Operation

9025TX,9025,GG1250 –19–09SEP97–2/3

NOTE: (Serial No. 546277—) The later designedswing torque control valve is now used for thelong front machines. (See Swing TorqueControl Valve Operation—For Long FrontMachines in this group.)

The swing torque control valve (X) is located betweenswing valve and control valve manifold.

When swing is actuated, pilot oil (U) is routed to theswing control valve pilot cap. Pilot oil is also routed toa passage (P or I) in control plate. The ball (O) inshuttle valve (Q) moves to route pilot oil through orifice(D) to the end of relief valve (A) poppet (C) and tospring side of pressure reducing valve (E).

The relief valve controls the maximum pilot oilpressure being routed to the pressure reducing valve.

The pressure reducing valve shuttle spool (L) sensesLS “load sense” oil from manifold (R) when swingvalve is actuated and LS oil from manifold (J) whenother functions are actuated and routes some of thehigher LS oil to the other LS from manifold passage.This reduces pump response time and limits swingpressure.

When one or multiple functions (S) are actuated alongwith swing, LS oil pressure from the one or multiplefunctions is routed to port (J). From port (J) LS oil isrouted to shuttle spool (L) and check valve (N). Checkvalve opens if the other LS oil pressure is higher. Fromthe check valve, LS oil pressure is routed to the swingvalve balance valves inside the spool. The higher LSoil pressure moves the balance valves to reduce oilflow going to the work ports.

05,109

TX,9025,GG1250 –19–09SEP97–3/3

T77

22A

G–1

9–31

AU

G92

The pressure reducing valve is shim adjustable. Addingshims increases the pressure setting moving the completeplot line (curve) (F, M, and C) up.

The angle of the plot line (curve) slope (M) is controlledby the amount of pilot oil pressure in the pressurereducing valve spring chamber. As pilot pressureincreases, spring force increases.

When the relief valve poppet opens (C), pilot oil pressureon the spring side of the pressure reducing valve hasreached its maximum specification.


PN=497

Theory Of Operation

902505

,110

TX,9025,LG53 –19–28AUG97–1/5

Swing Torque Control Valve OperationFor Long Front Machines—(Serial No. 546277—)

T11

0405

–19–

28O

CT

97


PN=498


Theory Of Operation

TX,9025,LG53 –19–28AUG97–2/5

A—Adjusting Screw G—Swing Torque Control K—Spring Guide O—OrificeB—Pin Valve Plate L—Plug (2 used) P—Plug (2 used)C—Plug H—Plug (4 used) M—Piston Q—Swing ValveD—Spring Guide I—Check Valve Ball N—Pressure Regulating Valve R—Swing Torque ControlE—Spring J—Spring Spool ValveF—Spring Guide

NOTE: (Serial No. 546277—) The long frontmachines also uses the later design swingtorque control valve.

The swing torque control valve (R) is located betweenswing valve (Q) and control valve manifold.

The function of the swing torque control valve is toregulate load sense oil from the swing valve to themain pump regulator to control pump output. Pump

output is controlled to allow maximum flow to theswing motor without opening the swing crossover reliefvalves.

(Serial No. 556936—)The swing torque control valve is of the same designand serves the same function as before. The boom,swing, and arm control valve manifold that the swingtorque control valve mounts to has changed.

902505,111



PN=499

Theory Of Operation

902505

,112

TX,9025,LG53 –19–28AUG97–3/5

B

C

RETURNPASSAGE

A ADJUSTINGSCREW

I CHECK VALVEG

G

I

D

F

H

J

B C DEORIFICESWING

VALVELOAD SENSEPASSAGE

H PRESSUREREGULATINGVALVE

SPOOL

PISTON

PUMP SUPPLYPASSAGE

D SWING VALVELOAD SENSEPASSAGE

F

TO MANIFOLDLOAD SENSEPASSAGE

E RETURNPASSAGE

D

SWING TORQUE CONTROL VALVE - SWING ACTUATED

SUPPLY OIL

P

L

LOAD SENSE OILM

REDUCED LOAD SENSE OILN

RETURN OILO

T8403AC CV

KT

8403

AC

–19–

22S

EP

97


PN=500


Theory Of Operation

9025TX,9025,LG53 –19–28AUG97–4/5

A—Adjusting Screw E—Return Passage I—Check Valve N—Reduced Load Sense OilB—Return Passage F—To Manifold Load Sense J—Spool O—Return OilC—Pump Supply Passage Passage K—Piston P—Swing Torque ControlD—Swing Valve Load Sense G—Orifice L—Supply Oil Valve—Swing Actuated

Passage H—Pressure Regulating Valve M—Load Sense Oil

When left or right swing is actuated (P), load sense oil(M) from the swing valve load sense passage (D) flowsto the pressure regulating valve (H). Load sense oilflows past the spool (J) land and is sensed at the topend of piston (K) pushing the spool (J) up against thespring regulating load sense oil. The reduced loadsense oil (N) flows out the port to the manifold loadsense passage (F) and then to the main pumpregulator. The main pump regulator controls the pumpoutput in response to the regulated load sense oilpressure from the swing torque control valve.

The pressure setting for pressure regulating valve isless than the swing crossover relief valve pressure

setting. The adjusting screw (A) is used to adjust thevalve pressure setting.

The check valve (I) is held closed by the higher loadsense oil pressure from the swing valve during swingoperation.

Return oil in return passage (B or E) is used todampen the spool movement on the spring end andthrough the orifice (G) on the piston end.

05,113



PN=501

Theory Of Operation

902505

,114

TX,9025,LG53 –19–28AUG97–5/5

G

I

D

F

B C DE

SWING TORQUE CONTROL VALVE - MULTIPLE FUNCTIONS

SUPPLY OIL

P

L

LOAD SENSE OILM

RETURN OILO

T8403AD CV

H PRESSUREREGULATINGVALVE

SWING VALVELOAD SENSE PASSAGE

D

FTO MANIFOLD LOADSENSE PASSAGE

I CHECK VALVE

D

J SPOOL

K PISTONH

T84

03A

D–1

9–02

SE

P97

B—Return Passage F—To Manifold Load Sense J—Spool O—Return OilC—Pump Supply Passage Passage K—Piston P—Swing Torque ControlD—Swing Valve Load Sense G—Orifice L—Supply Oil Valve—Multiple Functions

Passage H—Pressure Regulating Valve M—Load Sense Oil ActuatedE—Return Passage I—Check Valve

NOTE: The return passages from the swing valve andthrough the swing torque control valve areconnected together by a common returnpassage in the control valve manifold.

When one or more functions (P) are actuated alongwith swing, the highest load sense oil pressure fromthe other functions flows from the manifold load sensepassage (F) to the pressure regulating valve (H) and

check valve (I). The higher pressure sensed at the topend of piston (K) pushes the spool (J) up closing thepressure regulating valve and opens the check valve.From the check valve, load sense oil flows through theswing valve load sense passages (D) to the balancevalves inside the swing valve spool. The higher loadsense oil pressure moves the balance valve to controlthe pump supply oil flow through swing valve spool tothe swing motor.


PN=502

Theory Of Operation

902505,115


PN=503

Theory Of Operation

902505

,116

TX,9025,DY6292 –19–23OCT97–1/2

Pressure Control Manifold Operation (Serial No. —556935)

T111924 CV

SUPPLY OIL

PILOT OIL

N

O

P

Q

Z1

Z2

ORIFICE

CHECKVALVE

TO PUMPREGULATOR

LOAD SENSEOILRETURN OIL

FROM PROPELPILOT CHECK VALVE

POWERBOOSTSOLENOID

PRESSURE CONTROL MANIFOLD (S.N.—556935)



SAFETYRELIEFVALVE

FROMPILOTFILTERFROM ARM AND

BUCKET VALVES

PROPELACTUATED

DIG FUNCTIONACTUATED

COMBINEDFUNCTION SHUTTLEVALVE SPOOL

FROM BUCKET,ARM AND BOOMCONTROL VALVES

FROM PROPELCONTROL VALVES

AB

C

E

D

L

F

M M

AB

C

E

D

L

F

A

B

C

D

EF

G H

J

I

K

LM

R S

T

FROM BOOM,SWING, ANDAUXLILIARYVALVES

L

T11

1924

–19–

28O

CT

97


PN=504


Theory Of Operation

902505,117

TX,9025,DY6292 –19–23OCT97–2/2

POWER BOOSTSOLENOID

T8427AH CV

LOAD SENSEFROM MANIFOLD(DIG, SWING, AND AUXILIARY VALVES)

LOAD SENSEFROM CONTROLVALVE MANIFOLD

SPRING

TO PUMPREGULATOR

ORIFICE

CHECKVALVE


Z1FROM PROPELPILOT CHECKVALVE

(PROPEL VALVES)

Z2 FROMDIG VALVES

SAFETYRELIEFVALVE

SPOOL

TO CONTROLVALVE MANIFOLD


PRESSURE CONTROL MANIFOLD (S.N. —556935)

I

T

M

U

G

D

A

H E

F

V

J

C

B

L

Q SUPPLY OIL

R PILOT OIL

S LOAD SENSE OILT RETURN OIL

T84

27A

H–1

9–28

OC

T97

The pressure control manifold contains pilot pressureregulating valve (J), safety relief valve (H), load sensesystem relief valve (G) and combined function shuttlevalve (F).

Pilot oil (O) from pilot filter (K) is routed to the pilotpressure regulating valve. The pressure regulatingvalve limits the maximum allowable pilot pressure inthe circuit. Pilot oil is also routed to the power boostsolenoid (I). When activated by pressing the switch onthe top of right hand pilot controller the solenoid routespilot oil to the spring side of the load sense systemrelief valve (G). When not activated the solenoid routesthe oil on the spring side of the system relief to return.

Pump supply oil (N) from the control valve manifold isrouted to the safety relief valve (H). The safety relief

valve protects the hydraulic pumps. When pressure ismore than spring force plus load sense (P) pressure,the relief opens dumping the pressure spike to return.

Load sense oil from the control valve manifold (L) isrouted to the load sense system relief valve (G). Thesystem relief limits the maximum system pressure bymonitoring load sense pressure (work port pressure).Load sense oil is also routed to LS test port and topump regulator (C).

The combined function shuttle valve (F) is used toimprove propel metering during combined functionoperation.


PN=505

Theory Of Operation

902505

,118

TX,9025,LG54 –19–23OCT97–1/2

Control Valve Manifold Operation (Serial No. 556936—)

T110406

PROPEL ACTUATED

SUPPLY OIL

ORIFICE

R

PILOT OILS

LOAD SENSE OILT

RETURN OILU

W DIG FUNCTION ACTUATEDX

MK

IH

N

C

D

E

G

COMBINEDFUNCTION SHUTTLEVALVE SPOOL


FROM PILOTFILTER

TO SWING TORQUECONTROL VALVE

TO ARMCONTROLVALVE

TO BOOMCONTROLVALVE

CHECKVALVE



POWERBOOSTSOLENOID



LSA

Z2Z1

LS K

O

A

B

Q

P F

V

FROM PROPELPILOT CHECKVALVE

FROM PROPELAND BUCKETCONTROL VALVE

J

I FROM DIG SHUTTLEVALVE S1 PORTLINE

TO PUMP REGULATOR

CONTROL VALVE MANIFOLD OPERATION (S.N. 556936— )

H

L

N

M

J

L

MK

IH

N J

L

T11

0406

–19–

30O

CT

97


PN=506


Theory Of Operation

TX,9025,LG54 –19–23OCT97–2/2

The control valve manifold contains pilot pressureregulating valve (C), load sense system relief valve (Q)and combined function shuttle valve (K).

Pilot oil (S) from pilot filter (D) is routed to the pilotpressure regulating valve. The pressure regulatingvalve limits the maximum allowable pilot pressure inthe circuit. Pilot oil is also routed to the power boostsolenoid (A). When activated by pressing the switch onthe top of right hand pilot controller the solenoid routespilot oil to the spring side of the load sense systemrelief valve (Q). When not activated the solenoid routesthe oil on the spring side of the system relief to return.

Pump supply oil from the control valve manifold isrouted to the safety relief valve in the propel and

bucket control valve. The safety relief valve protectsthe hydraulic pumps. When pressure is more thanspring force plus load sense (T) pressure, the reliefopens dumping the pressure spike to return.

Load sense oil from the control valve manifold isrouted to the load sense system relief valve (Q). Thesystem relief limits the maximum system pressure bymonitoring load sense pressure (work port pressure).Load sense oil is also routed to LS test port and topump regulator (L).

The combined function shuttle valve (K) is used toimprove propel metering during combined functionoperation.

902505,119


PN=507

Theory Of Operation

902505

,120

TX,9025,DY6293 –19–09SEP97–1/2

Power Boost Solenoid Operation—Actuated (Serial No. —556935)

FROM PILOTPRESUREREGULATINGVALVE

TO SPRINGSIDE OFSYSTEM RELIEFVALVE

PLUG

PIN

SPRING STARWASHER

NOT USEDTHISAPPLICATION

TO RETURNSIDE OFSYSTEMRELIEFVALVE


FROM PILOTPRESSUREREGULATINGVALVE

POWER BOOST SOLENOID-ACTUATEDT7585AE CV

A

B

NOT USEDTHIS APPLICATION D TO RETURN

SIDE OFSYSTEM RELIEFVALVE

C

SPOOLE STAR

WASHERF

SPRINGG

H

PILOT OILK

RETURN OILL

JI F C D A C

M

T75

85A

E–1

9–22

SE

P97


PN=508


Theory Of Operation

TX,9025,DY6293 –19–09SEP97–2/2

Power boost is actuated by pushing the power boostswitch on top of the right hand dig pilot controller.

A electrical sensing signal is sent to the systemcontroller. The system controller sends a control signalto the power boost solenoid. The magnetic coil in thesolenoid moves pin (J) against spool (E) and spring(G) force. Pilot oil (K) from the pilot pressure regulatingvalve (A) is routed to the spring side of the load sensesystem relief valve (B).

System working pressure is then increased byapproximately 10%.

The system controller limits the time the function isactive for each push of the switch to 10 seconds.Length of time the function is active can not beaccumulated by continually pushing the switch.

902505,121


PN=509

Theory Of Operation

902505

,122

TX,9025,LG55 –19–28AUG97–1/2

Power Boost Solenoid Operation (Serial No. 556936—)

T110851

G

B CSOLENOID

FROMPILOTPUMP


POWER BOOST — DE-ACTIVATED SOLENOID



D

H

G

B CSOLENOID

FROMPILOTPUMP


POWER BOOST — ACTIVATED SOLENOID

D

A

A

PILOT OILE

RETURN OILF

POWER BOOST SOLENOID—(SERIAL NO. 556936— ) T11

0851

–19–

28O

CT

97


PN=510


Theory Of Operation

TX,9025,LG55 –19–28AUG97–2/2

Power boost is actuated by pushing the power boostswitch on top of the right hand dig pilot controller.

A electrical sensing signal is sent to the systemcontroller. The system controller sends a control signalto the power boost solenoid. The magnetic coil movesthe solenoid spool. Pilot oil (E) from the pilot pump (B)is routed to the spring side of the load sense systemrelief valve (D).

System working pressure is then increased byapproximately 10%.

The system controller limits the time the function isactive for each push of the switch to 10 seconds.Length of time the function is active can not beaccumulated by continually pushing the switch.

902505,123


PN=511

Theory Of Operation

902505

,124

TX,9025,LG56 –19–28AUG97–1/2

Load Sense System Relief Valve Operation

T110413 CV

H POWER BOOST

SYSTEM RELIEF VALVE

I LOAD SENSE PRESSURE

J PILOT OIL PRESSURE

K RETURN OIL

A C

B

A C

B

A C

B

L

(S.N. —556935)

(S.N. —556936)

D NORMAL OPERATION G RELIEF OPERATION

FROM POWERBOOSTSOLENOID

TOCONTROLVALVEMANIFOLD

FROMCONTROLVALVEMANIFOLD

A

L

B

C

ADJUSTMENTSCREW POPPET

E F

L

T11

0413

–19–

05S

EP

97


PN=512


Theory Of Operation

TX,9025,LG56 –19–28AUG97–2/2

The load sense system relief valve is a direct acting,screw adjustable relief that limits supply pressure bymonitoring load sense (LS) pressure.

Spring force plus reservoir pressure holds poppet (F)on its seat during normal operation (D). As load sensepressure (work port pressure) increases it acts on theface of poppet (F). When LS pressure is more than

spring force plus reservoir pressure the poppet opens(G) and dumps LS pressure to return.

When power boost (H) is activated pilot oil is routed tothe spring side of the poppet. Relief pressure isincreased because LS pressure now must overcomespring force and pilot oil pressure.

902505,125


PN=513

Theory Of Operation

902505

,126

TX,9025,LG57 –19–28AUG97–1/2

Safety Relief Valve Operation

J

SAFETY RELIEF VALVE

C

A

J

B

A

C

B

T110414 CV

NORMAL OPERATION

RELIEF OPERATION

SUPPLY OIL

LOAD SENSE PRESSURE

RETURN OIL

TO CONTROLVALVE MANIFOLD


POPPET

(S.N. —556935)

(S.N. 556936 —)

B

D

A

E

F

G

H

I


C

J

T11

0414

–19–

05S

EP

97


PN=514


Theory Of Operation

TX,9025,LG57 –19–28AUG97–2/2

The safety relief valve is a direct acting, shimadjustable relief that protects the main hydraulicpumps from pressure spikes.

Spring force plus load sense (LS) pressure (H) holdspoppet (E) on its seat. The valve works throughout thepressure range of the system. The higher the LSpressure, the higher the safety relief valve setting.

Whenever there is a hydraulic pressure spike or aproblem with system relief valve or the LS circuit, thepoppet will lift off its seat and dump supply oil (G) toreturn (I).

902505,127


PN=515

Theory Of Operation

902505

,128

TX,9025,DY6321 –19–16SEP97–1/2

Main Pump Operation (Serial No. —559602)

MAIN PUMP (S.N. —559602)

PUMP SUPPLY CONTROL OIL

PUMP DISCHARGE

P

M

PUMP DISPLACEMENT CONTROL OILN

RETURN OILO

B

C

D

E

F

SMALL CONTROL PISTON

CYLINDER BLOCK

GPILOTPUMP

H SWASH PLATE

IJ

L PUMPDISCHARGE

LARGE CONTROL PISTONPISTONS

SWASH PLATE

REGULATOR HOUSING

FEEDBACKSPRINGS

CYLINDERBLOCK

K

A

T111923

T11

1923

–19–

28O

CT

97

The main pump (P) is two section, axial piston,swashplate controlled. The pump is bolted to theengine flywheel housing. A flex coupler connects theengine flywheel to the input shaft of pump. There is a

drive shaft for each pump section and they areconnected by a splined coupler. The pilot pump (G) isbolted to the end of the main pump and is driven by asplined coupler.


PN=516


Theory Of Operation

9025TX,9025,DY6321 –19–16SEP97–2/2

Splined to the drive shafts are the cylinder blocks (Aand F). The front pump section is the one closest tothe engine. Each cylinder block has nine pistons (K).As the cylinder blocks rotate the pistons will move inand out by following the incline of the swashplates (Hand L).

When the pistons move out of their bores, they willdraw oil from the reservoir. Moving back into theirbores, they will force oil out the discharge ports (D andJ) and to the control valves.

The angle of the swashplates determines the amountof flow the pump delivers. To control pumpdisplacement, each pump section has control pistons(servo pistons) attached to the swashplates.

The small pistons (E) always have pump supplycontrol oil (M) pressure and are always trying to keepthe pump at maximum displacement.

Feedback springs (B) are used to center pumpsections when the pumps are operating.

On the opposite side of the swashplate are the largepistons (I). Oil pressure to the large pistons comesfrom the regulator (C) located on top of the pump.Controlling the amount of oil to the large pistons willdetermine the pump output. The large pistons are ableto move the small pistons back in their bores becauseof the area difference.

The control pistons are located on the outer side of theswashplate. The rotating groups (cylinder blocks) arein the center of the swashplate.

05,129


PN=517

Theory Of Operation

902505

,130

TX,9025,DY6294 –19–09SEP97–1/2

Main Pump Operation (Serial No. 559603—)

RETURN OILO

PUMP SUPPLYCONTROL OIL

M

PUMP DISPLACEMENTCONTROL OIL

N

P

IKL

E

B

D

PUMPDISCHARGE

SWASHPLATES

PISTONS

MAIN PUMP

LARGECONTROLPISTON

C

REGULATORHOUSING

A

CYLINDERBLOCK

G

PILOTPUMP

FEEDBACKSPRING SMALL

CONTROLPISTON

JPUMPDISCHARGE

HSWASHPLATE

T110415 CV

T11

0415

–19–

28O

CT

97

The main pump (P) is two section, axial piston,swashplate controlled. The pump is bolted to theengine flywheel housing. A flex coupler connects theengine flywheel to the input shaft of pump. There is adrive shaft for each pump section and they areconnected by a splined coupler. The pilot pump (G) isbolted to the end of the main pump and is driven by asplined coupler.

Splined to the drive shafts are the cylinder blocks (Aand F). The front pump section is the one closest tothe engine. Each cylinder block has nine pistons (K).As the cylinder blocks rotate the pistons will move inand out by following the incline of the swashplates (Hand L).


PN=518


Theory Of Operation

TX,9025,DY6294 –19–09SEP97–2/2

When the pistons move out of their bores, they willdraw oil from the reservoir. Moving back into theirbores, they will force oil out the discharge ports (D andJ) and to the control valves.

The angle of the swashplates determines the amountof flow the pump delivers. To control pumpdisplacement, each pump section has control pistons(servo pistons) attached to the swashplates.

The small pistons (E) always have pump supplycontrol oil (M) pressure and are always trying to keepthe pump at maximum displacement.

Feedback springs (B) are used to center pumpsections when the pumps are operating.

On the opposite side of the swashplate are the largepistons (I). Oil pressure to the large pistons comesfrom the regulator (C) located on top of the pump.Controlling the amount of oil to the large pistons willdetermine the pump output. The large pistons are ableto move the small pistons back in their bores becauseof the area difference.

The control pistons are located on the outer side of theswashplate. The rotating groups (cylinder blocks) arein the center of the swashplate.

902505,131


PN=519

Theory Of Operation

902505

,132

TX,9025,LG59 –19–28AUG97–1/1

Pump Displacement Solenoid Operation—(Serial No. —559602)

T111922 CV

PILOT OIL

SPOOL

DISPLACEMENTADJUSTMENT SCREWFROM

PILOT PUMP

SOLENOID

PUMP DISPLACEMENT SOLENOID DE-ENERGIZED

PUMP DISPLACEMENT SOLENOID ENERGIZED (S.N. —559602)

DISPLACEMENTADJUSTMENTSCREW

SOLENOID

FROM PILOT PUMPSPOOL

RETURN OIL

REGULATEDPILOT OIL

B

C

D

A

C

E

F

G

A

DB

I

H

T11

1922

–19–

28O

CT

97

The pump displacement solenoid de-energized (H),upper illustration, is in this position when all the pilotcontrollers are in neutral or when system pressure islow (approximately below 1850 psi).

The solenoid (A) receives a small current when theengine is running, but it is not enough to move thespool (B). Pilot oil (E) is routed to the displacementsolenoid and is blocked.

The displacement adjustment screw (C) adjustsregulated pilot oil (F) which is routed to the load sensevalve. This passage is open to return at low systempressure.

When the solenoid is energized (I), the spool (B) ismoved against the spring and opens a passage forpilot oil to flow. Pilot oil is regulated and routed to theload sense valve to decrease load sense differential,which will deswash the main hydraulic pump.

Turning the displacement adjustment screw “in”reduces the pressure signal that is routed to the largecontrol piston.

The operator selected work modes correspond topreset current signal levels for the displacementsolenoid. For example, in “PR” work mode the currentsignal level to the displacement solenoid is the highest,which corresponds to 65% pump flow.

When the hydraulic system is loaded, the solenoidcurrent signal increases (deswashing the pump) to limitthe pump load to the maximum available enginepower. The input signal to the system controller for thepump load comes from the engine speed sensor. Thesystem controller then sends a current signal to thedisplacement solenoid. The solenoid current signalreturns to the preset level when the hydraulic systemis unloaded. (See Control System Operation in thisgroup for more information.)


PN=520

Theory Of Operation

902505,133

TX,9025,LG59Z –19–16FEB00–1/1

Pump Displacement Solenoid Operation—(Serial No. 559603—)

PUMP DISPLACEMENT SOLENOID DE-ENERGIZED

PUMP DISPLACEMENT SOLENOID ENERGIZED

SOLENOID A

SOLENOID A

SPOOL B

SPOOL B


C


C

I

J

FROM DUALSOLENOIDBLOCK "D" PORT

D

FROM DUAL SOLENOIDBLOCK "D" PORT

D

REGULATEDPILOT OIL

E

PILOT OILF

TRAPPED OILG

RETURN OILHT110845 PUMP DISPLACEMENT SOLENOID OPERATION (SERIAL NO. 559603— ) T

1108

45–1

9–28

OC

T97

The pump displacement solenoid de-energized (I),upper illustration, is in this position when all the pilotcontrollers are in neutral or when system pressure islow (approximately below 1850 psi).

The solenoid (A) receives a small current when theengine is running, but it is not enough to move thespool (B). Pilot oil (F) is routed to the displacementsolenoid and is blocked.

The displacement adjustment screw (C) adjustsregulated pilot oil (E) which is routed to the load sensevalve. This passage is open to return at low systempressure.

When the solenoid is energized (J), the spool (B) ismoved against the spring and opens a passage forpilot oil to flow. Pilot oil is regulated and routed to theload sense valve to decrease load sense differential,which will deswash the main hydraulic pump.

Turning the displacement adjustment screw “in”reduces the pressure signal that is routed to the largecontrol piston.

The operator selected work modes correspond topreset current signal levels for the displacementsolenoid. For example, in “PR” work mode the currentsignal level to the displacement solenoid is the highest,which corresponds to 65% pump flow.

When the hydraulic system is loaded, the solenoidcurrent signal increases (deswashing the pump) to limitthe pump load to the maximum available enginepower. The input signal to the system controller for thepump load comes from the engine speed sensor. Thesystem controller then sends a current signal to thedisplacement solenoid. The solenoid current signalreturns to the preset level when the hydraulic systemis unloaded. (See Control System Operation in thisgroup for more information.)


PN=521

Theory Of Operation

902505

,134

TX,902505,SS638 –19–09SEP97–1/2

Pump Regulator—Minimum Displacement Operation (Serial No. —559602)

T7568AB1 CV PUMP REGULATOR - MINIMUM DISPLACEMENT

LOAD SENSEADJUSTMENTSCREW

SLEEVE

LARGECONTROLPISTON

SMALLCONTROLPISTON

HYDRAULICPUMP

LOADSENSESPOOL

FROMDUALSOLENOIDBLOCK

FROM PRESSURECONTROL MANIFOLD

TORESERVOIR

DISPLACEMENTADJUSTMENTSCREWSPRING

SPOOLFROMPILOTPUMP

PUMPDISPLACEMENTSOLENOID

ORIFICE

A

N

O

BD

E

F

G

H

I

J

KLM

C

SUPPLY OIL

PILOT OIL

RETURN OIL

S

P

Q

R

T75

68A

B1

–19–

02S

EP

97


PN=522


Theory Of Operation

TX,902505,SS638 –19–09SEP97–2/2

When the control valves are in neutral, the hydraulicsystem is a closed center system. The load sensesignal from the pressure control manifold (O) is atreservoir pressure. Pump supply (P) will always behigher than load sense pressure.

Pump supply oil will move the load sense spool (F) tothe left, opening a passage to the large control piston(C). An orifice (G) is located in the housing that allowsa small amount of oil from the large control piston (C)to flow to return. This provides for smooth operation ofthe load sense valve. Supply oil is routed to the smallcontrol piston (D) when the engine is running. Thesmall control piston and the large control piston areconnected to the swashplate. With equal oil pressure

on both pistons, the large one with more surface areadeswashes the pump to minimum displacement (S).

In neutral, the pump displacement solenoid (M) hasonly a small current applied, which is not enough tomove the spool (K) against the spring (J). Pilot oil (Q)from the pilot pump (L) is blocked by the spool.

The load sense valve is screw adjustable. If the loadsense pressure differential is set too high, the pumpcomes into stroke quickly causing jerky operation, andthe combined functions operation will cause the engineto lug down excessively. When the load sensepressure differential is set too low, the individualfunction operation will be slow.

902505,135


PN=523

Theory Of Operation

902505

,136

TX,9025,LG60 –19–28AUG97–1/2

Pump Regulator—Minimum Displacement Operation (Serial No. 559603—)

T110846

A

B



C


D

LARGECONTROLPISTON

E

SMALLCONTROLPISTON

G

LOADSENSESPOOL

HPUMPDISPLACEMENTSOLENOID

ISPOOL

JFROMDUALSOLENOIDBLOCK

K

O

SPRING

PUMP REGULATOR - MINIMUM DISPLACEMENT

F

HYDRAULICPUMP

SUPPLY OILL

RETURN OILM

PILOT OILN

T11

0846

–19–

28O

CT

97

When the control valves are in neutral, the hydraulicsystem is a closed center system. The load sensesignal from the control valve manifold (C) is at

reservoir pressure. Pump supply (L) will always behigher than load sense pressure.


PN=524


Theory Of Operation

TX,9025,LG60 –19–28AUG97–2/2

Pump supply oil will move the load sense spool (G) tothe left, opening a passage to the large control piston(D). This provides for smooth operation of the loadsense valve. Supply oil is routed to the small controlpiston (E) when the engine is running. The smallcontrol piston and the large control piston areconnected to the swashplate. With equal oil pressureon both pistons, the large one with more surface areadeswashes the pump to minimum displacement (N).

In neutral, the pump displacement solenoid (H) hasonly a small current applied, which is not enough to

move the spool (I) against the spring (K). Pilot oil (N)from the dual solenoid block (J) is blocked by thespool.

The load sense valve is screw adjustable. If the loadsense pressure differential is set too high, the pumpcomes into stroke quickly causing jerky operation, andthe combined functions operation will cause the engineto lug down excessively. When the load sensepressure differential is set too low, the individualfunction operation will be slow.

902505,137


PN=525

Theory Of Operation

902505

,138

TX,9025,LG61 –19–28AUG97–1/2

Pump Regulator—Fixed And Maximum Displacement (Serial No. —559602)

T7692AI CV


SLEEVE

LARGECONTROLPISTON

SMALL CONTROLPISTON

HYDRAULICPUMP LOAD

SENSESPOOL

FROM PRESSURECONTROL MANIFOLD

TORESERVOIR

A

F

H

G

J SUPPLY OIL

K LOAD SENSE OIL

L TRAPPED OIL

M RETURN OIL

PUMP REGULATOR - MAXIMUM DISPLACEMENT

C

D

B E

PUMP REGULATOR - FIXED DISPLACEMENT

LARGECONTROLPISTON

C

SLEEVEBLOAD SENSE

ADJUSTMENTSCREW

A

FROM PRESSURECONTROL MANIFOLD H

TORESERVOIR G

LOADSENSESPOOL

FE

HYDRAULICPUMP

SMALL CONTROLPISTON

D

N

I

T76

92A

I–1

9–22

SE

P97


PN=526


Theory Of Operation

TX,9025,LG61 –19–28AUG97–2/2

When pump supply oil (J) is equal to load sense plusspring force, the pump will be at fixed displacement (I).Oil to the large control piston will be trapped.

When a control lever is moved, pump supply will dropslightly. This will allow load sense oil (K) plus springforce to move the load sense spool (F) to the right andopen a passage from the large piston to the reservoir(G) (lower illustration). The small control piston in thepump always has pump supply pressure plus springforce acting on the swashplate. With the oil in the largecontrol piston connected to return, pump flow willincrease to maximum displacement (N).

If the pilot control levers are returned to neutral, orwhenever load sense pressure is low, pump supply will

move the load sense spool and connect the pumpsupply passage to the large control piston. Sendingpump supply oil to the large control piston deswashesthe pump. The pump will continue to deswash untilpump supply pressure and load sense pressure plusspring force equalize and again trap the oil in the largecontrol piston.

The load sense signal from the pressure controlmanifold (H) is equal to the highest work port pressure.Pump supply is a higher pressure than the highestwork port pressure.

902505,139


PN=527

Theory Of Operation

902505

,140

TX,9025,LG62 –19–28AUG97–1/2

Pump Regulator—Fixed And Maximum Displacement (Serial No. 559603—)



LARGECONTROLPISTON

SMALLCONTROLPISTON

HYDRAULICPUMP

LOADSENSESPOOL

TO RESERVOIR

PUMP REGULATOR - FIXED DISPLACEMENT

T110847

B

C D

F

G

H

A



LARGECONTROLPISTON

SMALLCONTROLPISTON

HYDRAULICPUMP

LOADSENSESPOOL

TO RESERVOIR

PUMP REGULATOR - MAXIMUM DISPLACEMENT (SERIAL NO. 559603— )

B

CD

E

F

G

I

A

SUPPLY OILJ

LOAD SENSEOIL

K

TRAPPED OILL

RETURN OILM

E

T11

0847

–19–

28O

CT

97


PN=528


Theory Of Operation

TX,9025,LG62 –19–28AUG97–2/2

When pump supply oil (J) is equal to load sense plusspring force, the pump will be at fixed displacement(H). Oil to the large control piston will be trapped.

When a control lever is moved, pump supply will dropslightly. This will allow load sense oil (K) plus springforce to move the load sense spool (F) to the right andopen a passage from the large piston to the reservoir(G) (lower illustration). The small control piston in thepump always has pump supply pressure plus springforce acting on the swashplate. With the oil in the largecontrol piston connected to return, pump flow willincrease to maximum displacement (I).

If the pilot control levers are returned to neutral, orwhenever load sense pressure is low, pump supply will

move the load sense spool and connect the pumpsupply passage to the large control piston. Sendingpump supply oil to the large control piston deswashesthe pump. The pump will continue to deswash untilpump supply pressure and load sense pressure plusspring force equalize and again trap the oil in the largecontrol piston.

The load sense signal from the control valve manifold(B) is equal to the highest work port pressure. Pumpsupply is a higher pressure than the highest work portpressure.

902505,141


PN=529

Theory Of Operation

902505

,142


PN=530

Theory Of Operation

TX,9025,LG63 –19–28AUG97–1/3

Pump Neutral Control Operation

T111926

SUPPLY OIL

PILOT OIL

TRAPPED OIL

RETURN OIL

S

T

U

V

W NEUTRAL CONTROL (S.N. —559602)

LOAD SENSEADJUSTMENT VALVESCREW

TORESERVOIR

PUMPDISPLACEMENTSOLENOID FROM PILOT

PUMP

LOAD SENSESPOOL

SPOOL

PUMPDISPLACEMENTADJUSTMENTSCREW

SMALL CONTROLPISTON

SWASHPLATE

LARGE CONTROLPISTON

DUALSOLENOIDBLOCK

SYSTEM CONTROLLERMANUAL BYPASSVALVE


PRESSURE CONTROLMANIFOLD

SAFETYRELIEFVALVE


CONTROL VALVE

CONTROLVALVE

A

R

QP

O

B

M

KL

C

E

F

G

H

I

J

N

D

T111926 –19–28OCT97


PN=531

Theory Of Operation

TX,9025,LG63 –19–28AUG97–2/3

N

A

LOAD SENSEVALVEADJUSTMENTSCREW


B

R

LOAD SENSESPOOL

Q

C D

E LOAD SENSE SYSTEMRELIEF VALVE

DUALSOLENOIDBLOCK


TO SAFETYRELIEFVALVE

SYSTEMCONTROLLERMANUALBYPASSVALVE


TOPUMPCASEDRAIN

SPOOL

FROM DUALSOLENOID BLOCK

SUPPLY OILS

PILOT OILT

TRAPPED OILU

RETURN OILV

SMALL CONTROLPISTON

LARGECONTROLPISTON

M

L

SWASHPLATE

K

W

CONTROLVALVE

NEUTRAL CONTROL (S.N. 559603 —)

J

CONTROL VALVEI

O

P

T110848 CV

E

F

T110848 –19–28OCT97

All main control valves are closed center. In neutral,the control valve spools block pump supply oil (S) flow.

Control valve sections (I and J) are shown in theneutral position.


PN=532

Theory Of Operation

902505,145

TX,9025,LG63 –19–28AUG97–3/3

With all main control valve sections in neutral, loadsense pressure from the control valves is at return oilpressure (V).

Pump supply oil pressure (S) will be approximately2758 kPa (28 bar) (400 psi). This pressure, acting onthe end of load sense spool (B) will overcome springforce and load sense pressure on the opposite endand open a passage from pump supply oil pressure tothe large control piston (L) deswashing the pump tominimum displacement.

In neutral, the pump displacement solenoid (Q) hasonly a small current applied which is not enough tomove the spool (O). Pilot oil (T) is blocked by thespool.

The large control piston is twice the diameter of thesmall control piston (M). Pump supply pressure willmove the large control piston to deswash the pumpswashplate (K) and put the pump at minimum flow.

Both pumps are controlled by the same load sensepressure and the large piston in both pumps are at

pump supply oil pressure. Both pump sections will beat a minimum flow.

The system controller manual override valve is open toreturn in neutral (at Serial No. 538539 a detent wasadded to manual override valve and style of knob waschanged). A check valve in the fitting on the pumpregulator prevents oil flow from the pump displacementsolenoid spool. If there is a system controllermalfunction, the operator can open the override valveto continue working until service can be preformed. Donot start engine with override valve open as enginewould start at “P” (max. power) power mode. The mainhydraulic pump operates at approximately 65—75%with the override valve open. Pilot oil is regulated bythe pressure regulator valve (E) and is routed to theload sense spool. This regulated oil pressure joins loadsense pressure and moves the load sense spool left.Load sense differential pressure is reduced thus pumpdisplacement would be decreased.


PN=533

Theory Of Operation

902505

,146


PN=534

Theory Of Operation

TX,9025,LG64 –19–28AUG97–1/3

Pump Low Pressure Control Operation

T111927 LOW PRESSURE CONTROL (S.N. —559602)

SUPPLY OIL

HIGHEST WORKPORTPRESSURE (LOAD SENSE)

LOWEST WORKPORTPRESSURE

PILOT OIL

REGULATED PILOTPRESSURE

RETURN OIL

T

U

V

W

X

YZ

WP

WP

WP

WP

P P

LS LS

LOAD SENSE VALVEADJUSTMENT SCREW

TORESERVOIR


LOAD SENSESPOOL

SPOOL


SMALL CONTROLPISTON

SWASHPLATE

LARGE CONTROLPISTON

DUALSOLENOIDBLOCK


SAFETYRELIEFVALVE


CONTROL VALVE

CONTROL VALVE

A

S

R

Q

B

O

MN

C

D

F

E

P

BALANCEVALVE

BALANCEVALVE

G

K

H SHUTTLEVALVE

I

JSHUTTLEVALVE

L

T111927 –19–28OCT97


PN=535

Theory Of Operation

TX,9025,LG64 –19–28AUG97–2/3

SMALL CONTROLPISTON

P

A

LOAD SENSE VALVEADJUSTMENTSCREW


B

S

LOAD SENSESPOOL

RPUMPDISPLACEMENTSOLENOIDSPOOL

LARGECONTROLPISTON

O

N

SWASHPLATEM

Q

T110849 CVLOW PRESSURE CONTROL (S.N. 559603— )

SUPPLY OIL

HIGHEST WORKPORTPRESSURE (LOAD SENSE)LOWEST WORKPORTPRESSUREPILOT OIL

REGULATED PILOTPRESSURERETURN OIL

T

U

V

W

X

Y

WP

WP

WP

WP

P P

LS LS

CONTROL VALVE

BALANCEVALVEBALANCE

VALVE

G

K

H SHUTTLEVALVEJ

I

SHUTTLEVALVE

CONTROLVALVE

L

Z

E

F


TOSAFETYRELIEFVALVE

D CONTROL VALVEMANIFOLD

DUALSOLENOIDBLOCK

CTORESERVOIR

T110849 –19–28OCT97


PN=536

Theory Of Operation

902505,149

TX,9025,LG64 –19–28AUG97–3/3

In this illustration, two control valve section (I and L)spools have been moved. Pump supply oil (T) isapplied to both control valve sections. Because ofload, control valve (L) has the highest work portpressure (U) and this moves shuttle valve (J) down.Highest work port pressure passes through balancevalve (K), around the shuttle spool and controls loadsense pressure.

The load sense spool (B) controls pump flow whensupply oil is below 12 411 kPa (124 bar) (1800 psi).

In low pressure control operation, pump supply oilacting on the end of the load sense spool, will alwaysbe below 12 411 kPa (124 bar) (1800 psi). Load senseoil plus spring force will move the load sense spool tothe right. This opens a path from the large controlpiston (N) by the load sense spool to the reservoir (S).

When load sense pressure and spring force on oneend of the load sense spool are equal to pump supplyoil on the opposite end, the load sense spool traps oilto the large control piston. Whenever the oil to thelarge control piston is trapped the pumps are

maintaining flow somewhere between minimum andmaximum flow.

If the load in the circuit with the highest work portpressure increases, highest work port pressureincreases, raising load sense pressure (U). Loadsense pressure and spring force act on the load sensespool, move the spool, opening a passage betweenreturn and the large control piston. This allows thesmall control piston (O) to increase swashplate angle,increasing pump flow.

If the load decreases, load sense pressure decreases.This allows pump supply oil acting on the load sensespool to overcome load sense pressure and springforce. This opens a passage between pump supply oiland the large control piston, decreasing swash andpump flow.

The load sense system relief valve (E) limits loadsense pressure. Since pump sections respond to loadsense pressure, if load sense pressure does notincrease, pump supply will not increase.


PN=537

Theory Of Operation

902505

,150


PN=538

Theory Of Operation

TX,9025,LG65 –19–28AUG97–1/3

Pump High Pressure Control Operation

HIGH PRESSURE CONTROL (S.N. —559602)Z

SUPPLY OIL

HIGHEST WORKPORTPRESSURE (LOAD SENSE)

LOWEST WORKPORTPRESSURE

PILOT OIL

REGULATED PILOTPRESSURE

RETURN OIL

T

U

V

W

X

YT111928


SAFETYRELIEFVALVE


CONTROL VALVE

BALANCEVALVE

BALANCEVALVE

SHUTTLEVALVESHUTTLE

VALVE

LOAD SENSE VALVEADJUSTMENT SCREW

TORESERVOIR

LOAD SENSESPOOL

SPOOL

DUALSOLENOIDBLOCK

A

SQ

B

C



SMALL CONTROLPISTON

SWASHPLATE

LARGE CONTROLPISTON

CONTROL VALVE

R

O

P

MN

L

D

F

E

G

K

H

I

J

WP

WP

WP

WP

P P

LS LS

T111928 –19–28OCT97


PN=539

Theory Of Operation

TX,9025,LG65 –19–28AUG97–2/3

WP

WP

WP

WP

P P

LS LS

P

S

A

LOAD SENSEVALVEADJUSTMENTSCREW


TORESERVOIR

B

C

LOAD SENSESPOOL

RPUMPDISPLACEMENTSOLENOID

DUALSOLENOIDBLOCK

SPOOLQ

T110850 CV

SHUTTLEVALVE

CONTROLVALVE

CONTROLVALVE

LARGECONTROLPISTON

N

SMALLCONTROLPISTON

O

M SWASHPLATE

BALANCEVALVE

HIGH PRESSURE CONTROL (S.N. 559603— )

G

BALANCEVALVE

K

SHUTTLEVALVE

J

I

L

Z

E

F

SUPPLY OIL

HIGHEST WORKPORTPRESSURE (LOAD SENSE)LOWEST WORKPORTPRESSUREPILOT OIL

REGULATED PILOTPRESSURERETURN OIL

T

U

V

W

X

Y

H


TOSAFETYRELIEFVALVE

D CONTROL VALVEMANIFOLD

T110850 –19–28OCT97


PN=540

Theory Of Operation

902505,153

TX,9025,LG65 –19–28AUG97–3/3

Pump supply oil (T) is controlled by the pumpdisplacement solenoid (P) any time pressure is above12 411 kPa (124 bar) (1800 psi). Engine horsepower isfixed. As pressure increases, pump flow mustdecrease to prevent stalling the engine.

Control valve (L) has the highest work port pressure(U) and is controlling load sense pressure. As pressureincreases, the difference between load sense andpump supply pressure becomes less. Above 12 411kPa (124 bar) (1800 psi), load sense pressure andspring force will overcome pump supply oil force onthe load sense spool (B). The pump displacementsolenoid now controls pump flow.

When machine load increases, pump supply oilpressure increases. The increased load decreasesengine speed which is sensed by the systemcontroller. The system controller sends a signal to thepump displacement solenoid (P) that moves spool (Q)to the right against the spring. This opens a passagefor pilot oil (W) that is regulated (X) to flow to the loadsense spool (B). This signal joins pump supply andmoves the load sense spool to the left, opening a

passage for pump supply oil to flow to the large controlpiston (N). Any time pump supply flows to the largecontrol piston, the pump deswashes and pump flowdecreases.

As the pump deswashes, the load on the enginedecreases. The system controller senses this and thepump displacement solenoid and spool remainstationary. Pump supply and regulated pilot oil willequalize with load sense oil and spring force. Thistraps oil to the large control piston. With oil trapped tothe large control piston, the pump will be heldsomewhere between minimum and maximum flow.

When machine load decreases, pump supply oilpressure decreases and engine speed increases. Thisis sensed by the system controller which provides onlya small current to the pump displacement solenoid.Spring force moves spool (Q) left and blocks pilot oil. Ifpump supply oil further decreases, the load sensespool would move right. This would open a passagefrom the large control piston to return. Pump flowwould again increase.


PN=541

Theory Of Operation

902505

,154


PN=542

Theory Of Operation

TX,9025,LG66 –19–28AUG97–1/3

Return Circuit OperationT110416 –19–28OCT97


PN=543

Theory Of Operation

TX,9025,LG66 –19–28AUG97–2/3

T110419 –19–29OCT97


PN=544

Theory Of Operation

TX,9025,LG66 –19–28AUG97–3/3

During normal propel operation oil returns from thepropel motors through the rotary manifold to thecontrol valve on earlier machines or to the propel andbucket control valve on later machines. Return oil fromthe swing motor is also routed through the maincontrol valve on earlier machines or through the boom,swing, and arm control valve manifold on latermachines. Approximately 50% of the return oil flowingto the control valve is routed to the reservoir throughthe oil cooler.

Return oil from the pilot shut off valve, pump regulator,and engine speed control actuator go directly to thereservoir.

When the oil is cold or the oil cooler is clogged, returnoil from the control valve flows directly back to thereservoir through the oil cooler bypass valve.

902505,157


PN=545

Theory Of Operation

902505

,158


PN=546

Theory Of Operation

TX,9025,LG67 –19–28AUG97–1/3

Drain Circuit OperationT110417 –19–28OCT97


PN=547

Theory Of Operation

TX,9025,LG67 –19–28AUG97–2/3

T110418 –19–29OCT97


PN=548

Theory Of Operation

TX,9025,LG67 –19–28AUG97–3/3

Internal leakage (lubrication oil) from the propel motorsand the swing motor returns to the reservoir throughthe drain circuit. Oil from the propel motors returnsthrough the rotary manifold. The drain oil from the

swing motor and the propel motors flows through thereturn filters. Case drain oil from the main hydraulicpump returns directly to the reservoir.

902505,161


PN=549

Theory Of Operation

902505

,162

TX,902505,SS652 –19–28FEB95–1/1

Hydraulic Reservoir

T84

28A

E–1

9–02

MA

R95

A—Cap F—To Hydraulic Pumps K—Hydraulic Oil Level Sender Q—Return FilterB—Hydraulic Breather Filter G—To Pilot Pump L—From Hydraulic Oil Cooler R—Filter Bypass ValveC—Inlet Screen H—Diffuser Screen M—From Rotary Manifold S—CoverD—Sight Tube I—Hydraulic Oil Temperature N—From Dual Solenoid Block T—SpringE—From Pump Regulator and Switch O—From Swing Gearbox U—From Hydraulic Pumps

Engine Speed Control J—From Control Valve (T1) P—From Pilot Shut-Off ValveActuator


PN=550

Theory Of Operation

902505,163

TX,902505,IJ138 –19–28FEB95–1/1

Cylinder Operation

T75

53C

K–1

9–29

JUL9

1

The boom, arm, and bucket cylinders are similar indesign. The arm cylinder is illustrated here. The rodguide is fastened to the cylinder barrel with cap screwsand is fitted with a bearing (E). The bearing is held isposition by a retaining ring (D). Three types of sealsare used in the rod guide., a step seal (F), U-cup seal(G), and wiper seal (H). The U-cup seal is protectedagainst high pressure by the step seal and stops asmall amount of oil which may pass by the step seal.A bearing (wear ring) (E) is located between the stepseal and the retaining ring.

The piston is a slip fit on the rod and is retained with anut (I). A shim is used between the piston and nut toprevent galling when the nut is tightened. The piston is

fitted with a cap seal (C), wear rings (B), and bufferseals (A).

Boom, bucket, and arm cylinders have a cushion infront of the piston to provide a cushioning action duringcylinder extension. As the cylinder nears the end of itsstroke the cushion enters a bore in the rod guide. Theremaining return oil ahead of the piston and nut mustflow through a small clearance as the cylinder bottomsout in this direction. Only the arm cylinder is cushionedin retraction. The end of the rod enters a bore in thehead end of the cylinder. The remaining return oilahead of the piston and nut must flow through thissmall clearance as the cylinder bottoms out in thisdirection.


PN=551

Theory Of Operation

902505

,164


PN=552

Group 10System Operational Checks

9025TX,9025,DY6295 –19–09SEP97–1/1

Hydraulic Operational Checks

This procedure is designed so the mechanic can makea quick check of the hydraulic system. If you needadditional information, read Theory of Operation,Group 9025-05.

A location will be required which is level and hasadequate space to complete the checks.

The engine and all other major components must be atoperation temperature for some checks.

Locate system check in the left column and readcompletely, following this sequence from left to right.Read each check completely before performing.

In the far right column, if no problem is found, you willbe instructed to go to next check or check is complete.

If problem is indicated you will be given repair requiredand Group location or CTM number. If verification isneeded, you will be given next best source ofinformation:

Group 10 (System Operational Checks)

Group 15 (Diagnostic Information)

Group 20 (Adjustments)

Group 25 (Tests)

CTM (Component Technical Manual)

101

– – –1/1

1 Hydraulic System Checks

– – –1/1

Visual Inspection Park machine on level surface.

T7531BA –UN–07JUN91

Extend bucket cylinder 3/4 stroke as shown.

Extend arm cylinder fully.

Lower bucket to ground.

Are cylinders dirty and muddy, which may show signs ofleaks?

YES: Repair leaks.

NO: Continue check.

T7531BC –UN–07JUN91

Check hydraulic oil level.

Is oil level between ADD and FULL lines on sightgauge?

Inspect oil lines and hydraulic components for leaks ordamage.

Are lines or components damaged or leaking?

YES: Repair leaks.Repair bent or damagedlines or components andfill tank to correct level.

NO: Go to next check.


PN=553

System Operational Checks

– – –1/1

Hydraulic Oil TankPressurization Check

T7531BD –UN–07JUN91

Raise boom to full height then lower boom to ground.

Move pilot shut-off lever to OFF.

Stop engine.

Loosen tank cap.

Is air heard escaping from tank?

NOTE: The tank is pressurized to create pressure athydraulic pump inlets. If cap does not seal, hydraulicpumps could cavitate and could be damaged.

YES: Go to next check.

NO: Replace breathervalve in breather filter.

902510

2

– – –1/1

Hydraulic Control LeverPattern (SAE Pattern)Check

T102070 –UN–16JUL96

T102071 –UN–16JUL96

CAUTION: Machine functions will move while performing this check.Operate machine in an open area.

Engine in “L” (light duty) mode.

Move pilot control shut-off lever to ON (forward).

Slowly move hydraulic control levers to all positions indicated on decals.

Do bucket, boom, arm and swing functions move as decals indicate?


NO: Install correct decalsfor operation pattern.


PN=554


9025– – –1/1

Hydraulic Control LeverPattern (John DeerePattern) Check

T102197 –UN–19JUL96

T102198 –UN–19JUL96

CAUTION: Machine functions will move while performing this check.Operate machine in an open area.


Move pilot control shut-off lever to ON (forward).

Slowly move hydraulic control levers to all positions indicated on decals.

Do bucket, boom, arm, and swing functions move as decals indicate?


NO: Install correct decalsfor operation pattern.

103

– – –1/1

Hydraulic SystemWarm-Up Procedure CAUTION: Machine functions will move while performing this check.

Operate machine in an open area.

NOTE: In cold weather, an extended warm-up period will be necessary. For fasterwarm-up, cover radiator and oil cooler during warming period. The hydraulic filterrestriction indicator may flicker during warm-up.

Start and run engine for 5 minutes.

Slowly cycle all functions.

IMPORTANT: Holding a function over relief for more than 10 seconds can causehot spots in the control valve.

Raise one track off ground. Rotate track while holding bucket curl function over relieffor 10 seconds then release bucket curl function for 5 seconds. Repeat cycle for 2-1/2minutes.

Lower track to ground. Cycle all hydraulic functions to circulate warm oil.

Does side of reservoir feel warm to touch?

YES: Warm-up complete.

NO: Repeat untilreservoir is warm totouch.


PN=555


9025 – – –1/1

Pilot Shut-Off ValveCheck

T7351CC –UN–22AUG90

CAUTION: Machine functions may movewhile performing this check. Operatemachine in an open area.


Pilot control shut-off lever in OFF rearward position.

Operate all dig and propel function controls.

Do any dig or propel functions operate?

YES: Adjust linkage. Goto 9025-20.

NO: Continue check.

T7351CB –UN–22AUG90

CAUTION: Machine functions will move whileperforming this check. Operate machine inan open area.

Push pilot control shut-off lever to the ON (forward)position.

Carefully operate all dig and propel functions.

Do all dig and propel functions operate?


NO: Adjust linkage. Go toGroup 9025-20. Do PilotValve Test andAdjustment. Go to Group9025-25.

104


PN=556


9025105

– – –1/2

Work Mode Check

T7321AR1 –UN–30AUG90

CAUTION: Make sure area is clear and largeenough to operate all functions of machine.

Start engine.

Is “L” (light duty) power mode indicator light ON?

Is “PR” (precision) work mode indicator light ON?

Pilot shut-off lever ON (forward).

Operate all dig functions, one at a time, and note speedof operation.

Do all functions operate slowly?

Push work mode select switch (A) until “EC” (economy)work mode indicator light (B) comes ON.

Does “E” (economy) power mode indicator light comeON and engine speed increase?


Are function speeds faster than speeds in “PR”(precision) work mode?

Push work mode select switch until “G” (general) workmode indicator light (D) comes ON.

Does “P” (max. power) mode indicator light come ONand engine speed increase slightly?


Are function speeds faster than speeds in “EC”(economy) work mode?

Push work mode select switch until “HD” (heavy duty)work mode indicator light (E) comes ON.

Does “P” (max. power) power mode indicator light stayON and engine speed increase?


Are function speeds faster than speeds in “G” workmode?


PN=557


902510

6

–19– –2/2

T7531AH –UN–07JUN91

NOTE: Three propel speeds are available in “HD” (heavyduty), “G” (general), and “EC” (economy) work modes atpower modes “L”, “E” or “P.”

Work mode at “HD” (heavy duty) mode. “HD” indicatorlight is ON.

Engine at “P” (max. power) mode. “P” indicator light isON.

Push propel speed increase switch (A) until high speedpropel (rabbit) indicator light (C) comes ON.

Propel machine on a level area and note propel speed.

Push propel speed decrease switch (B) until mediumspeed indicator light (D) comes ON.

Does propel speed decrease?

Push propel speed decrease switch (B) until low speedpropel (turtle) indicator light (E) comes ON.

Does propel speed decrease?

Push work mode select switch until “G” (general) workmode indicator light comes ON.

Does propel speed decrease slightly?

Push propel speed increase switch until medium propelspeed indicator light is ON.

Does propel speed stay the same?

Push propel speed increase switch until high speedpropel (rabbit) indicator light is ON.

Does propel speed increase?


NO: Check Engine SpeedControl LinkageAdjustment. Go to Group9010-20.

Check fuses. If fuses areOK, do System ControllerSensing Signals Check inthis group or go to Group9015-15.


PN=558


9025107

– – –1/1

Machine OperatingModes Check (DigFunctions Only)

Refer to the table below to see the relationship between work modes, power modes,percentage of hydraulic flow available, and propel speeds available.

Work mode automatically sets the power mode; however, you can choose a differentpower mode by pushing one of the power mode switches.

Set the propel speed manually using the propel speed increase and decreaseswitches.

WORK MODE POWER(HD: Heavy MODE

Duty) (P: Max PROPEL(G: General) Power) HYDRAULIC SPEEDS

(EC: (E: Economy) FLOW AvailableEconomy) (L: Light POWER Maximum (H: High)

(PR: Duty) MODE RPM Percentage of (M: Medium)Precision) (I: Low Idle) ± 30 Available (L: Low)

HD Pa 2150 100% AllE 1800 100% AllL 1300 100% AllI 900 75% H & Lb

Gc P a 1950 80% Alld

E 1800 80% Alld

L 1300 80% Alld

I 900 75% H & Lb

EC P 2150 80% Alld

Ea 1800 80% Alld

L 1300 80% Alld

I 900 75% H & Lb

PRe P 2150 65%f H & Lb

E 1800 65%f H & Lb

La 1300 65%f H & Lb

I 900 65%f H & Lb

aWork mode automatically selects this power mode.b"M" and "L" speeds are the same.cWhen "G" work mode is selected, the power mode is automatically set at "P" (1950rpm). If you push "P" power mode switch while operating in "G" work mode, max.power "P" mode rpm setting changes to 2150 rpm.dThere is only a 5% difference between "M" and "L" speeds.eWhen the engine is started, the machine is automatically set at "PR" work mode.fWhile propelling machine, available maximum hydraulic flow increases to 75%.


NO: See specificinformation on workmodes and power modesin Groups 9020-05 and9025-05 or Chapter 35 ofoperator’s manual.

See specific informationon propel modes inGroup 9020-05 orChapter 30 of operator’smanual.


PN=559


902510

8

– – –1/1

Pilot Pressure SwitchCheck

Engine running at “P” (max. power) mode.

Auto-idle OFF.

Pilot control shut-off lever to ON (forward).

Push auto-idle switch ON.

Does engine speed decrease to auto idle in 4—6 seconds?

Move hydraulic control lever to activate boom up, then return lever to neutral.

Does engine speed increase when hydraulic control lever is moved, then return to autoidle 4—6 seconds after control lever is returned to neutral?

Move hydraulic control lever to activate arm in, then return lever to neutral.

Does engine speed increase when control lever is moved, then return to auto idle 4—6seconds after control lever is returned to neutral?

Move hydraulic control lever to activate swing either direction, then return lever toneutral.

Does engine speed increase when control lever is moved, then return to auto idle 4—6seconds after control lever is returned to neutral?

Move control hydraulic lever to activate bucket in either direction, then return lever toneutral.

Does engine speed increase when control lever is moved, then return to auto idlespeed 4—6 seconds after control lever is returned to neutral?

Move either propel pedal or lever forward or reverse.

Does engine speed increase when control is moved, then return to low idle 4—6seconds after control is returned to neutral?


NO: Check fuse. If fuse isOK, do System ControllerSensing Signals Check inthis group or go to Group9015-15.

– – –1/1

2 Control Valve Checks

– – –1/1

Dig Function Drift Check

T7531AP –UN–07JUN91

Engine at “L” (light duty) mode.

Fill bucket with dirt and position bucket at maximumreach with bucket 95 mm (3-3/4 in.) above ground.

Observe bucket for one minute.

Does bucket drift down to ground within one minute?

YES: Excessive drift isindicated. Do CylinderDrift Test. Go to Group9025-25.



PN=560


– – –1/1

Control Valve Lift CheckChecks

T7531BB –UN–07JUN91

Engine at “L“ (light duty) mode.

Pilot control shut-off lever ON (forward).

Position machine as illustrated.

Slowly move control lever to the following positions, oneat a time: lower boom, extend arm (retract cylinder), anddump bucket (retract cylinder).

Do functions move in opposite direction as control leversare moved, then change direction as levers are movedfurther?

YES: If functions move inopposite direction first, aleak within the cylinder orbalance valve isindicated. Inspect andrepair. Go to Group 3360.


– – –1/1

3 Manual Override Valve Checks

9025109

– – –1/1

Manual Override ValveCheck

T109325 –UN–02JUN97

Engine running.

Turn manual override valve (A) 1/4 turn (90°) counterclockwise.

Does engine speed increase to “P” (max. power) mode?

NOTE: When override valve is turned, system controller does not regulate engine orhydraulic pump. Engine runs in “P” mode and hydraulic pump flow remains 60—70%.High hydraulic demand can stall the engine. Use care when operating controls.

Do all dig and propel functions operate?

IMPORTANT: Starting or stopping engine with override valve actuated maycause engine damage. Turn override valve to normal operating mode beforestarting or stopping engine.


NO: See Manual OverrideValve Test andAdjustment, Group9025-25.

– – –1/1

4 Cycle Time Checks


PN=561


90251010

– – –1/2

Cycle Time Checks

T6477AQ –UN–19OCT88 T7884AE –UN–10NOV92

CAUTION: Make sure area is clear and large enough to operate allfunctions of machine.

IMPORTANT: Warm hydraulic oil to operating temperature for this check.

Engine running.

Select “HD” (heavy duty) work mode

Engine at “P” (max. power) mode.

Auto-idle switch OFF.

Extend bucket cylinder (bucket empty).

Retract arm cylinder.


NOTE: Three propel speeds are available in “HD” (heavy duty) work mode and “L”,“E”, or “P” power mode (engine speed).

Push propel speed increase switch until high speed propel (rabbit) mode indicator lightis ON.

Does machine perform within specifications?

SpecificationBoom Raise (ground level to full heightwith bucket curled, arm extended)—Cycle Time 3.6—3.8 sec typical new.................................................................................Cycle Time 4.5 sec service limit........................................................................................Arm Out (cylinder retract)—Cycle Time 3.6—3.8 sec typical new.....................................Cycle Time 4.5 sec service limit........................................................................................Arm In1 (cylinder extend)—Cycle Time 4.4—4.7 sec typical new......................................Cycle Time 5.5 sec service limit........................................................................................Bucket Dump (cylinder retract)—CycleTime 2.6—2.7 sec typical new............................................................................................Cycle Time 3.2 sec service limit........................................................................................Bucket Curl (cylinder extend)—CycleTime 3.8—4.1 sec typical new............................................................................................Cycle Time 4.8 sec service limit........................................................................................Swing Left or Right—3 Revolution FromRunning Start (bucket curled, armretracted)—Cycle Time 16.0 sec typical new....................................................................Cycle Time 23.0 sec service limit......................................................................................

1 Setting of arm cylinder restrictor affects cycle time.


PN=562


–19– –2/2

SpecificationTrack Raised—3 Revolutions FromRunning Start (check in forward andreverse)—Cycle Time 16.5 sec typical new.......................................................................Cycle Time 24.0 sec service limit......................................................................................Propel 20 m (65 ft) (check in forwardand reverse)—Cycle Time 12.0—15.5 sec typical new.....................................................Cycle Time 20.0 sec service limit......................................................................................


NO: For slow functions,check hydraulic pumpflow. Go to Group9025-25. For a slowfunction, check hydrauliccircuit for that function.Go to Groups 9020-20,9020-25, 9025-20 and9025-25.

90251011


PN=563


90251012

– – –1/2

Cycle Time For LongFront Machine Checks

T6477AQ –UN–19OCT88 T7884AE –UN–10NOV92

CAUTION: Make sure area is clear and large enough to operate allfunctions of machine.

IMPORTANT: Warm hydraulic oil to operating temperature for this check.

Engine running.

Select “HD” (heavy duty) work mode

Engine at “P” (max. power) mode.

Auto-idle switch OFF.

Extend bucket cylinder (bucket empty).

Retract arm cylinder.


NOTE: Three propel speeds are available in “HD” (heavy duty) work mode and “L”,“E”, or “P” power mode (engine speed).

Push propel speed increase switch until high speed propel (rabbit) mode indicator lightis ON.

IMPORTANT: Because of the extra length, the boom and arm can be damaged ifcycle times are faster (less) than the times given. Never adjust the spool stopscrews to get cycle times faster than the times given.

Does machine perform within specifications?

SpecificationBoom Raise (ground level to full heightwith bucket curled, arm extended)—Cycle Time 7.0 sec............................................................................................................Arm Out (cylinder retract)—Cycle Time 7.4 sec................................................................Arm In1 (cylinder extend)—Cycle Time 8.2 sec.................................................................Bucket Dump (cylinder retract)—CycleTime 2.3 sec.......................................................................................................................Bucket Curl (cylinder extend)—CycleTime 2.3 sec.......................................................................................................................Swing Left or Right—3 Revolutions fromRunning Start (bucket curl, armretracted)—Cycle Time 27.0 sec.......................................................................................Track Raised—3 Revolutions fromRunning Start (check in forward andreverse)— Cycle Time 16.5 sec typical new.....................................................................Cycle Time 24.0 sec service limit......................................................................................

1 Setting of arm cylinder restrictor affects cycle time.


PN=564


–19– –2/2

SpecificationPropel 20 m (65 ft) (check in forwardand reverse)—Cycle Time 12.0—15.5 sec typical new.....................................................Cycle Time 20.0 sec service limit......................................................................................


NO: For slow functions,check hydraulic pumpflow. Go to Group9025-25. For a slowfunction, check hydrauliccircuit for that function, goto Groups 9020-20,9020-25, 9025-20 and9025-25.

– – –1/1

5 Swing Brake Checks

90251013

– – –1/1

Swing Brake ReleaseCheck

Push swing brake release switch.

Engine running at “P” (max. power) mode.

Park machine on an incline.

Fill the bucket with dirt.

Swing the upperstructure halfway up the hill and stop by allowing the hydraulic controllever to return to neutral.

Does upperstructure drift slightly?

NOTE: Some machines may not drift if tolerances in the hydraulic system are tight.

YES: Check complete.

NO: Swing brake may notbe releasing. Checkswing brake releasesignal to system controllercircuit. Go to Section9015.


PN=565


90251014


PN=566

Group 15Diagnostic Information

9025151

TX,9025,JH4 –19–23OCT97–1/6

Diagnose Hydraulic System Malfunctions

NOTE: Diagnose malfunction charts are arranged frommost probable and simplest to verify, to leastlikely and most difficult to verify.

Symptom Problem Solution

No Hydraulic Functions Low oil level Add oil.

Pilot shut—off valve in lock “OFF” Move lever to unlock “ON”.position

Pilot shut-off valve linkage Adjust linkage. See Group 9025-20.misadjusted

Pilot pump failure Remove pilot pump and inspect. SeeGroup 3360.

Pilot pressure regulating valve stuck Do Pilot Pressure Regulating Valveopen Test and Adjustment. See Group

9025-25.

Load sense differential pressure is Do Load Sense Differential Pressuretoo low Test And Adjustment. See Group

9025-25.

Safety relief valve stuck open Remove and Inspect.

Damaged suction lines Inspect replace if needed.

Hydraulic pump failure Do Hydraulic Pump Flow Test—FlowMeter Method. See Group 9025-25.

Some Hydraulic Functions Do Pilot controller Measure pilot pressure at controlNot Work valve pilot cap with function

actuated.

Pilot controller hoses pinched Inspect and correct.

Circuit relief valves misadjusted Do Circuit Relief Valve Test andAdjustment. See Group 9025-25.

Control valve spool stop screws Adjust spool stop screws. See Groupmisadjusted 3360.

Dig or propel check block Inspect check balls.


PN=567


Diagnostic Information

902515

2

TX,9025,JH4 –19–23OCT97–2/6


Pilot cap check valve missing Remove pilot cap and inspect. SeeGroup 3360.

Control valve spool stuck Remove pilot cap, manually movespool. See Group 3360.

One Function Does Not Work, All Pilot controller Measure pilot pressure at controlOthers Are Normal valve pilot cap with function

activated.

Circuit relief valve misadjusted Do Circuit Relief Valve Test AndAdjustment. See Group 9025-25.

Control valve spool stop screws Adjust stop screws. See Groupmisadjusted 9025-20.

Pilot hoses pinched Inspect and repair.

Pilot cap check valve plugged Remove pilot cap and inspect.

Control valve damaged Remove, disassemble and inspect.See Group 3360.

Cylinder damaged Inspect, check leakage.

All Hydraulic Functions Are Slow Cold oil Warm oil. See Warm-Up Procedureor Have Little Power Group 9025-25.

Pilot shut-off valve linkage Do Pilot Shut-off Valve Linkagemisadjusted Adjustment. See Group 9025-20.

Engine speed too slow Increase engine speed. Do SystemController Low Idle/High Idle CorrectCheck. See Section 9005.

Pilot filter plugged Replace filter.

Pilot pressure regulating valve Do Pilot Pressure Regulating Valvemisadjusted Test And Adjustment. See Group

9025-25.

Load sense system relief valve Do Load Sense System Relief Valvemisadjusted Test And Adjustment. See Group

9025-25.


PN=568



9025153

TX,9025,JH4 –19–23OCT97–3/6


Load sense differential pressure is Do Load Sense Differential Pressuretoo low Test And Adjustment. See Group

9025-25.

Damaged suction lines Inspect, replace if needed.

Pilot pump failure Remove and inspect. See Group3360.

Hydraulic pump failure Do Hydraulic Pump Flow Test—FlowMeter Method. See Group 9025-25.

Engine has low power Do Hydraulic Pump Flow Test—FlowMeter Method. See Group 9025-25.

Pressure control manifold problem Remove and inspect. See Group(Serial No. —559935) 3360.

Control valve manifold (Serial No. Remove and inspect. See Group559936—) 3360.

One Hydraulic Function Is Slow Pilot controller Measure pilot pressure at controlor Has Little Power valve pilot cap with function

activated.

Pilot controller hoses pinched Inspect, and correct.

Circuit relief valves misadjusted Do Circuit Relief Valve Test AndAdjustment. See Group 9025-25.

Control valve spool stop screws Adjust spool stop screws. See Groupmisadjusted 9025-20.

Pilot cap check valve missing Remove pilot cap and inspect. SeeGroup 3360.

Control valve spool sticking Remove pilot cap, manually movespool. See Group 3360.

Cylinder seals leaking Replace seals. See Group 3360.

Cylinder damaged Replace. See Group 3360.

Arm restrictor screw misadjusted Do Arm Cylinder RestrictorAdjustment in Group 9025-20.


PN=569



902515

4

TX,9025,JH4 –19–23OCT97–4/6


Hydraulic Cylinders Operate But Hydraulic oil level low Add oil.Cannot Lift Load

Load Sense System Relief Valve Do Circuit Relief Valve Test Andmisadjusted Adjustment. See Group 9025-25.

Pump suction line leaking Inspect suction line.

Hydraulic pump worn Do Hydraulic Pump Flow Test—FlowMeter Method. See Group 9025-25.

Hydraulic Oil Overheats High or low oil level Correct level.

Wrong oil Replace with correct oil.

Plugged radiator or oil cooler Clean radiator and straighten fins.

Radiator screen clogged. Remove and clean.

Plugged filters Install new filters.

Oil line restricted Inspect and repair.

Contaminated oil Drain oil and refill.

Oil cooler bypass Remove and inspect. See Group3360.

Relief valve leaking Remove and inspect all relief valves.

Air leak in pump suction line Inspect and replace.

Worn pump Do Hydraulic Pump Flow Test—FlowMeter Method. See Group 9025-25.

Propel motors leaking Do Propel Motor Leakage Test. SeeGroup 9025-25.

Water in oil Change Oil.

Kinks or dents in oil lines Check lines.

Air leak in line from reservoir to Repair leak.pump

Component failure Feel various hydraulic componentsfor excessive heat.


PN=570



9025155

TX,9025,JH4 –19–23OCT97–5/6


Swing Speed Slow in Both Low pilot system pressure All other functions will also be slow.Directions Do Pilot Pressure Regulating Valve

Test And Adjustment. See Group9025-25.

Spool stop screws Turn stop screws out.

Swing valve leakage Inspect swing valve. See Group3360.

Swing motor leakage Test swing motor leakage. SeeGroup 9025-25.

Worn pump, functions will be slow Do Hydraulic Pump Flow Test—FlowMeter Method. See Group 9025-25.

Swing Speed Slow or Does Not Swing make-up check valve leakage Inspect make-up valves. See GroupOperate in One Direction 3360.

Spool stop screws Turn stop screws out.

Swing crossover relief valve leakage Test swing crossover relief valves.See Group 3360.

Pilot controller malfunction Inspect pilot controller. See Group3360.

Upperstructure Drift With Swing Swing crossover relief valve leakage Inspect make-up valves. See GroupValve in Neutral 3360.

Swing motor leakage Test swing motor for leakage. SeeGroup 9025-25.

Swing brake not engaging Inspect swing brake. See Group4311.

Manual bypass valve is actuated Set to normal. See Section 9025.

Swing Function Does Not Swing brake release solenoid Test solenoid, pressure switch andOperate malfunction relay. See Section 9015.

Pilot controller Measure pilot pressure at swingvalve pilot cap.

Stuck swing crossover relief valve Inspect crossover relief valve. SeeGroup 3360.


PN=571



TX,9025,JH4 –19–23OCT97–6/6


Mechanical failure of swing motor or Disassemble components togearbox determine cause of failure.

Stuck main control valve Inspect main control valve. SeeGroup 3360.

902515

6


PN=572


9025157

DX,HYSYM –19–24AUG90–1/1

Hydraulic Circuit Symbols

TS

700

–19–

28S

EP

89


PN=573


902515

8


PN=574


TX,9025,DY6304 –19–11SEP97–1/1

Pilot Circuit Component Location (Serial No. —556935)T110420 –19–29OCT97


PN=575


TX,9025,DY6303 –19–11SEP97–1/2

Main Hydraulic Circuit Component Location (Serial No. —556935)T110421 –19–29OCT97


PN=576


TX,9025,DY6303 –19–11SEP97–2/2

T110422 –19–22SEP97


PN=577


TX,9025,DY6302 –19–11SEP97–1/1

Pilot Circuit Component Location (Serial No. 556936—)T110425 –19–22SEP97


PN=578


TX,9025,DY6319 –19–12SEP97–1/2

Main Hydraulic Circuit Component Location (Serial No. 556936—)T110423 –19–29OCT97


PN=579


TX,9025,DY6319 –19–12SEP97–2/2

T110426 –19–29OCT97


PN=580


TX,9025,LG68 –19–28AUG97–1/3

Main Hydraulic Schematic (Serial No. —556935)T109812 –19–28OCT97


PN=581


TX,9025,LG68 –19–28AUG97–2/3

T109815 –19–28OCT97


PN=582


TX,9025,LG68 –19–28AUG97–3/3

T109816 –19–28OCT97


PN=583


TX,9025,LG69 –19–28AUG97–1/4

Main Hydraulic Schematic (Serial No. 556936—)T109825 –19–28OCT97


PN=584


TX,9025,LG69 –19–28AUG97–2/4

T109826 –19–28OCT97


PN=585


TX,9025,LG69 –19–28AUG97–3/4

T109828 –19–28OCT97


PN=586


TX,9025,LG69 –19–28AUG97–4/4

T110260 –19–28OCT97


PN=587


90251522

TX,902515,SS661 –19–15MAR95–1/2

Pilot Control Lever Pattern Information

Excavator pilot control levers can be changed from thestandard pattern (SAE) to a John Deere pattern. Tochange to John Deere pattern:

1. Lower bucket to the ground.

2. Turn auto-idle switch off.

3. Run engine in “L” (light duty) power mode without loadfor 2 minutes.

4. Set power mode to “I” (low idle). Turn key switch toOFF to stop engine. Remove key from switch.

5. Move pilot control shut-off lever to locked position.

CAUTION: The hydraulic system is pressurized.Turn hydraulic tank fill cap slowly. Release allpressure before you remove cap.

6. Turn reservoir fill cap slowly to release air pressure.Then remove cap.

7. Open left service door. The dig pilot check valve blockis located below the air cleaner.



PN=588


90251523

TX,902515,SS661 –19–15MAR95–2/2

T83

26A

G–U

N–2

6SE

P94

Dig Pilot Check Valve Block

A—Pilot Controller Side B—From Pilot Controllers C—To Main Control Valve Pilot D—Main Control Valve SideCaps

8. Port identifying numbers are stamped on the digpilot check valve block.

9. Switch hoses in ports G2 and K2.

10. Switch hoses in ports H2 and L2.

CAUTION: Prevent injury from unexpectedmachine function. Install new decals oncontrol consoles.

11. Install new decals on control consoles near thebase of control levers. Decals are enclosed in theOperator’s Manual package. Additional decals canbe purchased from your John Deere dealer.


PN=589


90251524

TX,9025,GG1262 –19–17MAR95–1/2

Pilot Controller Lines—John Deere Pattern

T76

81A

W–U

N–1

3JA

N92

Left Pilot Controller

T76

81A

X–U

N–1

3JA

N92

Right Pilot Controller

LEFT PILOT CONTROLLER TO DIG PILOT CHECK VALVEBLOCK

FROM FUNCTION TO

1 SWING RIGHT E2

2 BOOM LOWER L2

3 SWING LEFT F2

4 BOOM RAISE K2

Port identification numbers are located next to theports on the left and right controller and dig pilot checkvalve block.

RIGHT PILOT CONTROLLER TO DIG PILOT CHECK VALVEBLOCK

FROM FUNCTION TO

1 BUCKET CURL I2

2 ARM IN G2

3 BUCKET DUMP J2

4 ARM OUT H2



PN=590


90251525

TX,9025,GG1262 –19–17MAR95–2/2

T83

26A

G–U

N–2

6SE

P94


A—Pilot Controller Side B—From Pilot Controllers C—To Control Valve Pilot D—Control Valve SideCaps

DIG PILOT CHECK VALVE BLOCK TO MAIN CONTROL VALVE PILOT CAP

FROM FUNCTION TO PILOT CAP PORT

E1 SWING RIGHT B

F1 SWING LEFT A

G1 ARM IN A

H1 ARM OUT B

I1 BUCKET CURL (CYLINDER EXTEND) A

J1 BUCKET DUMP (CYLINDER RETRACT) B

K1 BOOM RAISE A

L1 BOOM LOWER B



PN=591


90251526

TX,9025,GG1264 –19–17MAR95–1/2

Pilot Controller Lines—Standard Pattern (SAE)

T76

81A

W–U

N–1

3JA

N92

Left Pilot Controller

T76

81A

X–U

N–1

3JA

N92

Right Pilot Controller

LEFT PILOT CONTROLLER TO DIG PILOT CHECK VALVEBLOCK

FROM FUNCTION TO

1 SWING RIGHT E2

2 ARM OUT H2

3 SWING LEFT F2

4 ARM IN G2


RIGHT PILOT CONTROLLER TO DIG PILOT CHECK VALVEBLOCK

FROM FUNCTION TO

1 BUCKET CURL I2

2 BOOM RAISE K2

3 BUCKET DUMP J2

4 BOOM LOWER L2



PN=592


90251527

TX,9025,GG1264 –19–17MAR95–2/2

T83

26A

G–U

N–2

6SE

P94


A—Pilot Controller Side B—From Pilot Controllers C—To Control Valve Pilot D—Control Valve SideCaps

DIG PILOT CHECK VALVE BLOCK TO MAIN CONTROL VALVE PILOT CAP

FROM FUNCTION TO PILOT CAP PORT

E1 SWING RIGHT B

F1 SWING LEFT A

G1 ARM IN A

H1 ARM OUT B

I1 BUCKET CURL (CYLINDER EXTEND) A

J1 BUCKET DUMP (CYLINDER RETRACT) B

K1 BOOM RAISE A

L1 BOOM LOWER B



PN=593


90251528


PN=594

Group 20Adjustments

902525,AA4 –19–28FEB95–1/1

JT05800 Digital Thermometer Installation

T68

08C

E–U

N–2

8FE

B89

SERVICE EQUIPMENT AND TOOLS

Digital Thermometer

A—Temperature ProbeFasten to a bare metal line using a tie band. Wrap with shop towel.

B—Cable

C—Digital Thermometer

9025201


PN=595

Adjustments

902520

2

TX,902525,GG158 –19–07MAR95–1/1

Hydraulic System Warm-Up Procedure

SPECIFICATIONS

Oil Temperature 50 ± 6°C (120 ± 10°F)

Below 0°C (32°F) an extended warm-up period may benecessary. Hydraulic functions will move slowly andlubrication of parts may not be adequate with cold oil.Do not attempt normal machine operation untilhydraulic functions move at or close to normal cycletimes.

Operate functions slowly and avoid suddenmovements until engine and hydraulic oils arethoroughly warmed.

SpecificationOil—Temperature 50 ± 6°C (120 ± 10°F)............................................

Operate a function by moving it a short distance ineach direction. Continue operating the functionincreasing the distance traveled in each cycle until fullstroke is reached.

For faster warm-up, restrict air flow through oil coolerusing cardboard or other similar material. Use correctviscosity oil to minimize warm-up period. (SeeHydraulic Oil in Fuels and Lubricants group.)

1. Install temperature probe on reservoir-to-pump inletline. (See JT05800 Digital Thermometer Installationin this group.)

CAUTION: Avoid possible serious injuryfrom machine movement during warm-upprocedure. Clear the area of all personnelbefore doing the warm-up procedure.

2. Clear the area of all personnel to allow for machinemovement.

3. Start engine.

4. Push auto-idle switch to turn off auto-idle function(auto-idle indicator OFF).

5. Turn upperstructure so boom is to the side.

CAUTION: Avoid possible serious injuryfrom machine sliding backwards. Keep anglebetween boom and arm at 90—110°.

6. Keeping the angle between boom and arm at 90—110°, lower boom to raise track off the ground.

7. Push “M” (work mode select) switch to operate in“HD” work mode (heavy duty mode—HD indicatorON) and max. power mode (P indicator ON).

8. Push propel speed increase (right arrow) switch tooperate at high speed propel (rabbit—high speedpropel mode indicator ON).

IMPORTANT: Holding a function over relief formore than 10 seconds can causedamage from hot spots in thecontrol valve.

9. Operate the bucket curl function over relief and thepropel function (with track off the ground) for 10seconds and then stop for 5 seconds. Repeat thecycle until oil is heated to specifications.

10. Stop periodically and operate all hydraulicfunctions to distribute the heated oil.


PN=596

Adjustments

9025203


PN=597

Adjustments

902520

4

TX,9025,DY6305 –19–11SEP97–1/2

Lower Boom With Engine Stopped

T76

99A

O–U

N–2

3FE

B92


T10

9446

–UN

–02J

UN

97


T85

42A

V–U

N–1

2OC

T95

A—Spool Stop ScrewB—Lock NutC—Relief ValveD—Anti-Drift ValveE—Anti-Drift Valve Housing

With engine stopped, boom cannot be lowered by usingpilot control valve. The control valve spool must be movedmanually.

CAUTION: Clear all persons from the area whenlowering the boom with the engine stopped.

NOTE: For machines with an anti-drift valve (D), the reliefvalve (C) must be loosened 1/4 turn to make apassage through the valve for oil to flow from thecylinders to the control valve.

1. For machines with an anti-drift valve, loosen reliefvalve (C) in anti-drift valve housing (E) 1/4 turn.

2. Hold spool stop screw (B), located at rear of maincontrol valve, and loosen lock nut (A) until it is held onby only one or two threads.


PN=598


Adjustments

9025205

TX,9025,DY6305 –19–11SEP97–2/2

3. Counting the number of turns, turn spool stop screw in(clockwise) until screw contacts spool (increasedresistance).

4. Turn screw an additional one or two turns until boombegins to lower.

5. Record total number of turns screw was turned in.

6. Lower bucket to the ground.

CAUTION: Spool stop screw must be returnedto its original position after boom has beenlowered to avoid unexpected boom movement(lowering) when engine is started. Also functionspeed is affected if spool stop screw is notreturned to its original position.

7. Turn spool stop screw out the same number of turnsrecorded in Step 5 to return it to its original position.Tighten lock nut.

For machines with anti-drift valve (D), tighten reliefvalve (C) in anti-drift valve housing (E).


PN=599

Adjustments

902520

6

TX,9025,DY6326 –19–17SEP97–1/2

Raise Boom With Engine Stopped

T80

48A

C–U

N–1

7JU

L93


T10

9283

–UN

–02J

UN

97


With the engine stopped, boom cannot be raised usingpilot control valve. The control valve boom spool must bemoved manually.

CAUTION: Clear all persons from the area whenraising the boom with the engine stopped.

1. Hold spool stop screw (B) in front of boom section,loosen lock nut (A) until it is held on by only one or twothreads.

2. While counting the number of revolutions, turn thespool stop screw in until screw contacts spool(increased resistance).

3. Turn spool stop screw an additional 4—6 turns tomove spool enough to allow boom to be raised.


PN=600


Adjustments

9025TX,9025,DY6326 –19–17SEP97–2/2

T10

9187

–UN

–02J

UN

97

4. Attach an external lifting device to the guidelink-to-bucket pin (C).

5. Lift the bucket to ground level.

CAUTION: Boom cylinder must be blocked tomaintain boom position. Boom cylinder will notcontain enough oil to hold the boom in positionhydraulically.

6. Block the boom cylinder.

CAUTION: Return spool stop screw and locknut to original position after boom has beenraised to avoid unexpected boom movement(raising) when engine is started.

7. While counting the number of turns, return spool stopscrew to original position. Tighten lock nut. Functionspeed is affected if spool stop screw is not returned toits original position.

207


PN=601

Adjustments

902520

8

TX,9025,DY6306 –19–11SEP97–1/3

Swing Upperstructure With Engine Stopped

T80

48A

D–U

N–1

7JU

L93


T10

9448

–UN

–02J

UN

97


With engine stopped, upperstructure cannot be swungusing pilot control valve. The control valve swing spoolmust be moved manually.

To swing upperstructure to the right: Use the rear cap onthe main control valve as shown. Loosen lock nut (A).Turn screw (B) in.


PN=602


Adjustments

9025209

TX,9025,DY6306 –19–11SEP97–2/3

T76

99A

R–U

N–2

3FE

B92


T10

9447

–UN

–02J

UN

97


To swing upperstructure to the right: Use the rear cap onthe main control valve.

1. Hold spool stop screw (B), loosen lock nut (A) until it isheld on by only one or two threads.

2. While counting the number of turns, turn spool stopscrew (B) clockwise until the screw contacts spool(increased resistance).

3. Turn spool stop screw an additional 4—6 revolutions tomove spool sufficiently to swing upperstructure.

4. Disconnect swing brake release hose. Install plug inthe line.


PN=603


Adjustments

90252010

TX,9025,DY6306 –19–11SEP97–3/3

T75

81A

C–U

N–2

9JU

L91

5. Attach an external pressure source to the brakerelease fitting (A).

CAUTION: Clear all persons from the area whenswinging the upperstructure with the enginestopped.

6. Apply pressure of 1380—3450 kPa (13.8—34.5 bar)(200—500 psi) to the swing brake release fitting torelease the swing brake.

7. With external source, lift and swing boom away fromexcavation.

8. When upperstructure is in desired position, releasepressure from swing brake to apply brake.

9. Disconnect pressure source.

10. Connect swing brake release hose to brake releasefitting.

CAUTION: Return spool stop screw and locknut to original position after swinging theupperstructure to avoid unexpected swingmovement when engine is started.

11. While counting number of turns, return spool stopscrew to original position. Tighten lock nut. Functionspeed is affected if spool stop screw is not returnedto its original position.


PN=604

Adjustments

90252011

TX,902520,UU735 –19–30SEP94–1/1

Pilot Shut-Off Valve Linkage Adjustment

T76

60A

L–1

9–06

DE

C91

A—Shut-Off Lever C—Shut-Off Valve D—Lever E—Cap ScrewB—Rod

SPECIFICATIONS

Lever-to-Cap Screw Clearance 1.5 ± 0.5 mm (0.06 ± 0.02 in.)

1. Stop engine.

2. Remove cover from left console (beside seat) inoperator’s station.

3. Remove cover underneath operator’s station. (Ifequipped).

4. Push pilot shut-off lever (A) forward to the ONposition. Adjust ball joints on rod (B) ends tospecified clearance between lever (D) and capscrew (E).

SpecificationLever-to-Cap Screw—Clearance 1.5 ± 0.5 mm (0.06 ± 0.02 in.).............................................

CAUTION: Machine may move if adjustmentis incorrect. Prior to checking shut-off leveradjustment, make sure the area aroundmachine is clear.

5. Check adjustment by pulling shut-off lever (A) up tothe OFF position. Start engine and set enginespeed at low idle. Move pilot control levers.Hydraulic functions must NOT operate. If functionsmove, repeat adjustment procedure.


PN=605

Adjustments

90252012

TX,9025,DY6307 –19–11SEP97–1/2

Arm Cylinder Restrictor (Rod End) Adjustment

T76

98A

H–U

N–2

3FE

B92


T84

37A

A–U

N–2

0MA

R95

(Serial No. 546277—556935)

T11

0909

–UN

–08S

EP

97


A—Arm Regenerative Valve (Serial No. 546277—556935)

B—Arm Cylinder RestrictorC—Arm Control Valve

SPECIFICATIONS

Hydraulic Oil Temperature 50 ± 6°C (120 ± 10°F)

Power Mode Engine Speed “E” (Economy Mode)

Work Mode “M” “EC” (Economy Mode)


JT05800 Digital Thermometer

The arm cylinder restrictor is used to restrict the return oilflow from arm cylinder rod end. When the arm is extendedand then arm-in function is activated, the weight of armand bucket can cause the arm (extend cylinder) to movefaster than pump can supply oil to the head end ofcylinder causing cavitation. Too much restriction, capscrew turned in too far, will cause the cycle time for armcircuit to be slow.

Adjustment is made by watching arm during arm-infunction. Adjustment is correct when arm does not stop asit reaches a vertical position.


PN=606


Adjustments

90252013

TX,9025,DY6307 –19–11SEP97–2/2

IMPORTANT: Whenever attachments are changed, thearm restrictor screw adjustment mayneed to be changed to compensate forchanges in weight.

1. Install temperature probe on reservoir-to-pump inletline. (See JT05800 Digital Thermometer Installation inthis group.)

2. Heat hydraulic oil to specifications. (See HydraulicSystem Warm-Up Procedure in this group.)

SpecificationHydraulic Oil—Temperature 50 ± 6°C (120 ± 10°F)...................................

3. Run at specifications and select correct work mode.

SpecificationPower Mode—Engine Speed “E” (Economy Mode)....................................Work—Mode “M” “EC” (Economy Mode)....................................................

4. Raise boom and fully extend arm (cylinder retracted).

5. Fully actuate arm-in while observing arm movement.

6. Loosen nut on cap screw (B). Turn cap screw in toincrease restriction to prevent cavitation if arm stops atmid-stroke.


PN=607

Adjustments

90252014

TX,9025,LG70 –19–28AUG97–1/1

Boom Cylinder Restrictor (Head End)Adjustment (Serial No. 556936—)

T11

1010

–UN

–08S

EP

97

SPECIFICATIONS

Hydraulic Oil Temperature 50 ± 6°C (120 ± 10°F)

Power Mode Engine Speed “E” (Economy Mode)

Work Mode “M” “EC” (Economy Mode)


Digital Thermometer

The boom cylinder restrictor is used to restrict the returnoil flow from boom cylinder head end. When the boom islowered from the raised (cylinder extended) position,gravity pulls the boom down faster than the pump cansupply oil to the rod end of cylinder causing cavitation.Too much restriction, cap screw turned in too far, willcause the cycle time for boom circuit to be slow.

IMPORTANT: Whenever attachments are changed, theboom restrictor screw adjustment mayneed to be changed to compensate forchanges in weight.



SpecificationHydraulic Oil—Temperature 50 ± 6°C (120 ± 10°F)...................................

3. Run at specifications and select correct work mode.

SpecificationPower Mode—Engine Speed “E” (Economy Mode)....................................Work—Mode “M” “EC” (Economy Mode)....................................................

4. Raise boom (cylinder extended) and extend arm.

5. Fully actuate boom lower function while observingboom movement.

6. Loosen nut on cap screw (A). Turn cap screw in toincrease restriction to prevent cavitation.


PN=608

Adjustments

90252015


PN=609

Adjustments

90252016

TX,9025,LG71 –19–28AUG97–1/3

Control Valve Spool Stop Screw Adjustment

T76

98A

I–U

N–2

3FE

B92

Stop Screws Front Of Valve (Serial No. —556935)

T76

98A

J–U

N–2

3FE

B92

Stop Screws Rear Of Valve (Serial No. —556935)

T11

0906

–UN

–12S

EP

97

Stop Screws Front Of Valve (Serial No. 556936—)

T11

0907

–UN

–12S

EP

97

Stop Screws Rear Of Valve (Serial No. 556936—)

A—Swing Left D—Boom Lower G—Left Propel Forward J—Right Propel ReverseB—Swing Right E—Bucket Curl H—Left Propel Reverse K—Arm RetractC—Boom Raise F—Bucket Dump I—Right Propel Forward L—Arm Extend


PN=610


Adjustments

90252017

TX,9025,LG71 –19–28AUG97–2/3

T11

0908

–UN

–12S

EP

97

Stop Screws For Propel And Bucket Valve (Serial No. 556936—)

E—Bucket CurlF—Bucket DumpG—Left Propel ForwardH—Left Propel ReverseI—Right Propel ForwardJ—Right Propel Reverse

NOTE: The spool stop screws limit the travel of controlvalve spools. The control valve spools control thevolume of oil flow through its housing. The volumeof oil flow determines the speed (cycle time) of afunction.

The spool stop screws are set for optimum speed(cycle time) from the factory. Turning the propelspool stop screws out further than the factorysetting will cause a slight increase in propelspeed. Turning stop screws out too far will causeerratic boom operation (jerky) when boom israised as the machine is being propelled.

The number of turns given are a starting point forsetting the function speed (cycle time). Use cycletimes as the final determination for setting thespeed of a function.

SPECIFICATIONS

Power Mode Engine Speed Engine stopped

Swing Function Stop Screw 10-1/4Approximate Turns

Propel Function Stop Screw 10-1/2Approximate Turns

Boom Function Stop Screw 12Approximate Turns

Arm Function Stop Screw 12Approximate Turns

Bucket Function Stop Screw 12Approximate Turns

1. Loosen nut on each spool stop screw.

SpecificationPower Mode—Engine Speed Engine stopped............................................

2. Turn screw in until contact is just made with spool.

3. Turn screw out the specified number of turns.

SpecificationSwing Function Stop Screw—Approximate Turns 10-1/4...........................................................................Propel Function Stop Screw—Approximate Turns 10-1/2...........................................................................Boom Function Stop Screw—Approximate Turns 12.................................................................................


PN=611


Adjustments

TX,9025,LG71 –19–28AUG97–3/3

SpecificationArm Function Stop Screw—Approximate Turns 12.................................................................................Bucket Function Stop Screw—Approximate Turns 12.................................................................................

4. While holding screw, tighten nut.

5. Check the cycle time of functions adjusted.

90252018


PN=612

Adjustments

90252019


PN=613

Adjustments

90252020

TX,9025,SS2006 –19–14MAR95–1/3

Control Valve Spool Stop Screw AdjustmentFor Long Front Machine

NOTE: The spool stop screws limits the travel of controlvalve spools. The control valve spools control thevolume of oil flow through its housing. The volumeof oil flow determines the speed (cycle time) of afunction.

The spool stop screws are set for optimum speed(cycle time) from the factory. Turning the propelspool stop screws out further than the factorysetting may cause a slight increase in propelspeed. Turning stop screws out too far will causeerratic boom operation (jerky) when boom israised as the machine is being propelled.

The adjustment lengths given are a starting pointfor setting the function speed (cycle time). Usecycle times as the final determination for settingthe speed of a function.

SPECIFICATIONS

Power Mode Engine Speed Engine Stopped

Swing Right Function Screw 10.0 mm (0.39 in.)Adjustment Length

Swing Left Function Screw 10.0 mm (0.39 in.)Adjustment Length

Right Propel (Forward and 12.0 mm (0.47 in.)Reverse) Function ScrewAdjustment Length

Left Propel (Forward and 12.0 mm (0.47 in.)Reverse) Function ScrewAdjustment Length

Boom Up Function Screw 6.0 mm (0.24 in.)Adjustment Length

Boom Down Function Screw 9.5 mm (0.37 in.)Adjustment Length

Arm Out Function Screw 8.5 mm (0.33 inc.)Adjustment Length

Arm In Function Screw 9.5 mm (0.37 in.)Adjustment Length

Bucket Curl Function Screw 9.0 mm (0.35 in.)Adjustment Length

Bucket Dump Function Screw 9.5 mm (0.37 in.)Adjustment Length


PN=614


Adjustments

TX,9025,SS2006 –19–14MAR95–2/3

1. Engine Off.

SpecificationPower Mode—Engine Speed Engine Stopped...........................................

90252021

TX,9025,SS2006 –19–14MAR95–3/3T

7989

AT

–UN

–27A

PR

93

A—Valve SpoolB—Stop ScrewC—NutD—Pilot CapE—Adjustment Length

NOTE: For valve spool locations, see Control Valve SpoolStop Screw Adjustment in this group.

2. Loosen nut (C) on spool stop screw (B).

3. Adjust stop screw in pilot cap (D) to length (E) given.

SpecificationSwing Right Function Screw—Adjustment Length 10.0 mm (0.39 in.)........................................................Swing Left Function Screw—Adjustment Length 10.0 mm (0.39 in.)........................................................Right Propel (Forward andReverse) Function Screw—Adjustment Length 12.0 mm (0.47 in.)........................................................Left Propel (Forward andReverse) Function Screw—Adjustment Length 12.0 mm (0.47 in.)........................................................Boom Up Function Screw—Adjustment Length 6.0 mm (0.24 in.)..........................................................Boom Down Function Screw—Adjustment Length 9.5 mm (0.37 in.)..........................................................Arm Out Function Screw—Adjustment Length 8.5 mm (0.33 inc.).........................................................Arm In Function Screw—Adjustment Length 9.5 mm (0.37 in.)..........................................................Bucket Curl Function Screw—Adjustment Length 9.0 mm (0.35 in.)..........................................................Bucket Dump Function Screw—Adjustment Length 9.5 mm (0.37 in.)..........................................................

4. Check the cycle time of functions adjusted.


PN=615

Adjustments

90252022


PN=616

Group 25Tests

902025,AA75 –19–16SEP92–1/1

JT05801 Clamp-On Electronic TachometerInstallation

T68

13A

G–U

N–2

8FE

B89


Tachometer

A—Clamp-On Tachometer.Remove paint using emery cloth and connect to a straight section ofinjection line within 100 mm (4 in.) of pump. Finger tighten only—DONOT over tighten.

B—Black Clip (-). Connect to main frame.

C—Red Clip (+). Connect to transducer.

D—Tachometer Readout. Install cable.

9025251

902525,AA4 –19–28FEB95–1/1

JT05800 Digital Thermometer Installation

T68

08C

E–U

N–2

8FE

B89


Digital Thermometer

A—Temperature ProbeFasten to a bare metal line using a tie band. Wrap with shop towel.

B—Cable

C—Digital Thermometer

TX,9020,DW1349 –19–24JUN97–1/1

JT02156A Digital Pressure And TemperatureAnalyzer Installation

T85

43A

I–U

N–2

5AU

G95

A—Digital Pressure and Temperature AnalyzerB—3400 kPa (35 bar) (500 psi) Transducer34 000 kPa (350 bar) (5000 psi) Transducer70 000 kPa (700 bar) (10,000 psi) Transducer

Use the digital pressure and temperature analyzer inplace of analog gauges and a separate temperaturereader.

Transducers (B) are temperature sensitive. Allowtransducer to warm to system temperature. Aftertransducer is warmed and no pressure is applied, pushsensor zero button for one second to set true zero point.

When using for different pressures, turn selector to OFFfor two seconds and then to the pressure range. Readingsare inaccurate if proper range for transducer is not used.


PN=617

Tests

902525

2

TX,902525,GG158 –19–07MAR95–1/1

Hydraulic System Warm-Up Procedure

SPECIFICATIONS


Below 0°C (32°F) an extended warm-up period may benecessary. Hydraulic functions will move slowly andlubrication of parts may not be adequate with cold oil.Do not attempt normal machine operation untilhydraulic functions move at or close to normal cycletimes.

Operate functions slowly and avoid suddenmovements until engine and hydraulic oils arethoroughly warmed. Operate a function by moving it ashort distance in each direction. Continue operatingthe function increasing the distance traveled in eachcycle until full stroke is reached.

For faster warm-up, restrict air flow through oil coolerusing cardboard or other similar material. Use correctviscosity oil to minimize warm-up period. (SeeHydraulic Oil in Fuels and Lubricants group.)


CAUTION: Avoid possible serious injuryfrom machine movement during warm-upprocedure. Clear the area of all personnelbefore doing the warm-up procedure.

2. Clear the area of all personnel to allow for machinemovement.

3. Start engine.

4. Push auto-idle switch to turn off auto-idle function(auto-idle indicator OFF).

5. Turn upperstructure so boom is to the side.

CAUTION: Avoid possible serious injuryfrom machine sliding backwards. Keep anglebetween boom and arm at 90—110°.

6. Keeping the angle between boom and arm at 90—110°, lower boom to raise track off the ground.

7. Push “M” (work mode select) switch to operate in“HD” work mode (heavy duty mode—HD indicatorON) and max. power mode (P indicator ON).

8. Push propel speed increase (right arrow) switch tooperate at high speed propel (rabbit—high speedpropel mode indicator ON).

IMPORTANT: Holding a function over relief formore than 10 seconds can causedamage from hot spots in thecontrol valve.

9. Operate the bucket curl function over relief and thepropel function (with track off the ground) for 10seconds and then stop for 5 seconds. Repeat thecycle until oil is heated to specifications


.

10. Stop periodically and operate all hydraulicfunctions to distribute the heated oil.


PN=618

Tests

9025253

TX,9025,LG72 –19–28AUG97–1/1

Hydraulic Pump Start-Up Procedure

T75

27D

X–U

N–1

5JU

L91


T75

27D

Y–U

N–1

5JU

L91


T10

9313

–UN

–02J

UN

97


IMPORTANT: Pump will be damaged if not filled withoil before starting engine. Proceduremust be done whenever a new pump isinstalled or whenever oil has beendrained from the pump or reservoir.

Procedure is to ensure the pump is filled with oil and air isbleed from suction side of pump to prevent cavitation.

1. Fill reservoir so oil level is at center line of sight tube.

2. For machines (Serial No. —559602):

a. Remove plug (A) from bleed port.

b. Disconnect drain hose (B).

c. Add oil to pump case through the drain port until oilflows from bleed port.

d. Connect drain hose (B).

e. Install plug (A).

For machines (Serial No. 559603—):

a. Remove plugs (A and B).

b. Add oil to pump case through holes until oil level isto the top of case.

c. Install plugs (A and B).

3. Start engine and operate machine for several minutes.

4. Check oil level.


PN=619

Tests

9025 TX,902525,GG162 –19–21AUG91–1/1

Swing Motor Start-Up Procedure

T72

25A

U–U

N–1

0MA

R90

IMPORTANT: Motor will be damaged if not filled withoil before operating swing function.Procedure must be performed whenevera new motor is installed or oil has beendrained from the motor.

Procedure is to ensure the motor is filled with oil.

1. Disconnect swing motor drain line (A).

2. Open the bleed screw located between the crossoverrelief valves.

3. Fill motor with hydraulic oil through drain port (B) untiloil reaches the level of drain port.

4. Connect drain line.

5. Close bleed screw.

254

TX,902525,GG163 –19–21AUG91–1/1

Swing Brake And Gearbox Start-UpProcedure

IMPORTANT: Failure to fill swing gearbox and brakewith oil before operating swing functionmay result in damage. Procedure mustbe performed whenever a new swinggearbox or brake is installed or oil hasbeen drained from the gearbox andswing brake.

Procedure is to ensure the swing gearbox and brake arefilled and there is a flow of oil for lubrication and coolingbefore operating the swing function.

Start engine and run for 4—5 minutes before operatingswing function to ensure swing gearbox and brake arefilled and there is a flow of oil for lubrication and cooling.


PN=620

Tests

902525,F4A –19–18JUL94–1/1

Hydraulic Oil Filter Inspection Procedure

IT46

33–U

N–1

9JA

N90

Pour oil out of filter to inspect for water contamination.

Use an oil filter cutting tool to cut top off filter.

Remove element and inspect for metal particles anddebris in bottom of filter can.

Excessive amounts of brass and steel particles canindicate a failed hydraulic pump or a pump failure inprocess.

A rubber type of material can indicate cylinder packingfailure.

9025255


PN=621

Tests

902525

6

TX,902525,GG185 –19–23OCT97–1/2

Hydraulic Oil Cleanup Procedure Using Portable Filter Caddy

SPECIFICATIONS

Reservoir Capacity 148 L (39 gal)

Reservoir Approximate Filtering 13 minutesTime

System Capacity 265 L (70 gal)

System Approximate Filtering 42 minutesTime

ESSENTIAL TOOLS

JT03291 (3/4 M NPT x 3/4 M NPT) Elbow


Portable Filter Caddy

Two 3658 mm (12 ft) x 3/4 in. I.D. 100R1 Hoses with 3/4 M NPT

Quick Disconnect Fittings

Discharge Wand

Procedure is used to clean contamination from thehydraulic system after a hydraulic component failure.The Hydraulic Oil Cleanup Procedure Using Clean-UpFilter can also be used or used as a follow-up to thefilter caddy to ensure a complete cleanup ofcontamination. (See procedure in this group.)

The hydraulic system return filter can be cut apart andinspected for indications of contamination.

1. Install a new return filter element.

IMPORTANT: The minimum ID of connector mustbe 1/2 in. to prevent cavitation offilter caddy pump.

NOTE: For a failure that creates a lot of debris, drainthe reservoir. Remove access cover fromreservoir. Connect filter caddy suction line todrain port. Add a minimum of 19 L (5 gal) of oilto reservoir. Wash out the reservoir using thefilter caddy. Check and clean the suction linesto the main hydraulic pump and pilot pump.

2. To minimize oil loss, pull a vacuum in reservoirusing a vacuum pump. Connect filter caddy suction

line to quick disconnect fitting. Check to be suredebris has not closed drain port.

3. Put filter caddy discharge wand into reservoir fillerhole so end is as far away from drain port aspossible to obtain a thorough cleaning of oil.

4. Start the filter caddy. Check to be sure oil is flowingthrough the filters.

Operate filter caddy until all the oil in reservoir hasbeen circulated through the filter a minimum of fourtimes.

SpecificationReservoir—Capacity 148 L (39 gal).....................................................Reservoir—ApproximateFiltering Time 13 minutes.....................................................................

Leave filter caddy operating for the next step.

NOTE: Filtering time for reservoir is 0.089 minute xnumber of liters (0.33 minutes x number ofgallons).

5. Start the engine and run it at fast idle.

IMPORTANT: For the most effective results,cleaning procedure must start withthe smallest capacity circuit thenproceed to the next largest capacitycircuit.

6. Starting with the smallest capacity circuit, operateeach functions through a complete cycles.

Repeat procedure until the total system capacityhas circulated through filter caddy seven times.

SpecificationSystem—Capacity 265 L (70 gal)........................................................System—Approximate FilteringTime 42 minutes...................................................................................

Each function must go through a minimum of threecomplete cycles for a thorough cleaning of oil.


PN=622


Tests

TX,902525,GG185 –19–23OCT97–2/2

NOTE: Filtering time for complete hydraulic system is0.158 minute x number of liters (0.6 minutes xnumber of gallons). Filtering time for machineswith auxiliary hydraulic circuits must beincreased because system capacity is larger.

7. Stop the engine. Remove the filter caddy.

8. Install new return filter elements.

9. Check oil level in reservoir, add oil if necessary.(See Hydraulic Oil in Fuels and Lubricants group.)

9025257

TX,9025,GG1256 –19–14MAR95–1/3

Hydraulic Oil Cleanup Procedure UsingClean-Up Filter

Work Mode “M” “HD” (Heavy Duty)

Maximum Power Mode (Engine “E” (Economy)Speed)

Machine Minimum Operating One hourTime with Clean-up Filter

Machine Maximum Operating Three hoursTime with Clean-up Filter


AT162766 Clean-up Filter Element

For a failure that creates a lot of debris, do the HydraulicCleanup Procedure Using Portable Filter Caddy beforeusing the clean-up filter.



PN=623

Tests

902525

8

TX,9025,GG1256 –19–14MAR95–2/3

T84

37A

C–U

N–2

0MA

R95

1—Cap Screw (6 used)2—Cover3—O-Ring4—Spring5—Filter Bypass Valve6—Return Filter Element7—Cap Screw (3 used)8—Diffuser Screen (Filter)9—O-Ring10—Gasket11—Flange Nut (14 used)12—Washer (14 used)13—Filler Cap14—Gasket15—Access Cover16—Inlet (Filler) Screen17—Reservoir

1. Remove filler cap (13) to release air pressure.

2. Drain the oil or use the portable filter caddy to removeoil from reservoir.

3. Remove cover (2). Remove the spring (4), filter bypassvalve (5) and original filter element (6).

4. Inspect bypass valve seat for damage. Replace asnecessary.

5. Remove and clean the diffuser screen (8).

6. Remove access cover (15). Clean interior of reservoirusing lint-free towels.

7. Clean the suction lines to the main hydraulic pump andpilot pump.

8. Install the diffuser screen.

9. Install a new clean-up filter element. Install the filterbypass valve and spring. Install the covers.

10. Fill reservoir with clean oil to the correct level. (SeeHydraulic Oil in the Fuels and Lubricants group.)

IMPORTANT: Pump will be damaged if not filled withoil before starting engine. Proceduremust be done whenever a new pump isinstalled or whenever oil has beendrained from the pump or reservoir.

11. Do the Hydraulic Pump Start-Up Procedure. (Seeprocedure in this group.)



PN=624

Tests

9025259

TX,9025,GG1256 –19–14MAR95–3/3

T84

37A

C–U

N–2

0MA

R95

1—Cap Screw (6 used)2—Cover3—O-Ring4—Spring5—Filter Bypass Valve6—Return Filter Element7—Cap Screw (3 used)8—Diffuser Screen (Filter)9—O-Ring10—Gasket11—Flange Nut (14 used)12—Washer (14 used)13—Filler Cap14—Gasket15—Access Cover16—Inlet (Filler) Screen17—Reservoir

IMPORTANT: To avoid opening the filter bypass valvewith clean-up filter installed, run theengine at no more than “E” (economy)power mode (1700—1900 rpm). Runningthe engine at “P” (max. power) powermode will cause the filter bypass valveto open because of the greater oil flowfrom pump.

12. Start engine. Operate machine at specifications.

SpecificationWork—Mode “M” “HD” (Heavy Duty)..........................................................Maximum Power Mode—EngineSpeed “E” (Economy)..................................................................................

IMPORTANT: Operate the machine for no more thanthree hours with clean-up filter installedto prevent possible hydrauliccomponent damage.

13. Operate all hydraulic functions for not less than onehour but no more than three hours.

SpecificationMachine—Minimum OperatingTime with Clean-Up Filter One hour...........................................................Maximum Operating Time withClean-Up Filter Three hours........................................................................

Stop engine.

14. Remove filler cap to release air pressure.

15. Remove the clean-up filter element.

16. Install a new return filter element.


PN=625

Tests

90252510

TX,9025,LG73 –19–28AUG97–1/3

Pilot Pressure Regulating Valve Test And Adjustment

T77

01A

X–U

N–2

3FE

B92


T11

0912

–UN

–08S

EP

97


T76

98A

K–U

N–2

3FE

B92


T11

0913

–UN

–08S

EP

97


SPECIFICATIONS


Work Mode “M” “HD” (Heavy Duty Mode)

Power Mode Engine Speed “L” (Light Duty Mode)

One Shim Changes Pressure 138 kPa (1.4 bar) (20 psi)

Pilot System Regulating Valve 3000—4200 kPa (30—42 bar)Pressure Setting (435-610 psi)

ESSENTIAL TOOLS

A—38H1031 (—8 M x--8 F x —8M ORFS) (Parker No. 8R6L0-S)Tee

B—JT03457 (—8 F ORFS x 7/16-20 M 37°) or C—JT03749 (1/2 x13/16-16 UN ORFS) Adapter or Male Quick Coupler


PN=626


Tests

9025TX,9025,LG73 –19–28AUG97–2/3


JT02156A Digital Pressure and Temperature Analyzer or Gauge0—7000kPa (0-70 bar) (0—1000 psi)

JT02162 Transducer 35 000 kPa (350 bar) (5000 psi)


The pilot pressure regulating valve is located in thepressure control manifold. Pilot circuit pressure iscontrolled by the valve.

1. Remove reservoir fill cap to release air pressure.

2. Install test fittings (A and B) and pressure gauge.


4. Heat hydraulic oil to specifications.


(See Hydraulic System Warm-Up Procedure in thisgroup.)

5. Run at specifications.

SpecificationWork—Mode “M” “HD” (Heavy Duty Mode).........................................Power Mode—Engine Speed “L” (Light Duty Mode)............................

6. Record gauge pressure.

2511

TX,9025,LG73 –19–28AUG97–3/3

T75

76A

T–U

N–1

6AU

G91


7. For machines (Serial No. —556935), adjust pressuresetting by adding or removing shims (D) to pilotpressure regulating valve (C).

SpecificationOne Shim Changes—Pressure 138 kPa (1.4 bar) (20 psi)........................Pilot System Regulating Valve—Pressure Setting 3000—4200 kPa (30—42 bar)

(435—610 psi).........................................

For machines (Serial No. 556936—), adjust pressuresetting by adjusting screw (E).

If pressure setting does not respond to adjustment,remove and inspect regulating valve.


PN=627

Tests

90252512

TX,9025,LG74 –19–28AUG97–1/2

System Relief Valve Test And Adjustment

SPECIFICATIONS



Power Mode Engine Speed “P” (Max. Power)

System Relief Valve Pressure 34 500—36 200 kPa (345—362Setting bar) (5000—5250 psi)

1/4 Turn of Screw Changes 1725 kPa (17 bar) (250 psi)Pressure

ESSENTIAL TOOLS

JT03111 (7/16-20 M 37° x 9/16-18 M ORB) or AH125760 (1/2 x9/16-18 ORB) Fitting or Male Quick Coupler (Serial No. —556935)



JT02156A Digital Pressure and Temperature Analyzer or Gauge 0—70 000 kPa (0—10,000 psi)

Transducer 70,000 kPa (700 bar) (10 000 psi)

The system relief valve limits pump supply pressure for allfunctions. Test will verify if all function pressure are withinspecifications.





PN=628

Tests

90252513

TX,9025,LG74 –19–28AUG97–2/2

T76

98A

L–U

N–2

3FE

B92


T11

1911

–UN

–28O

CT

97


3. Install fitting (A) and gauge to “P” test port in pressurecontrol manifold (Serial No. —556935) or “P” test portin control valve manifold (Serial No. 556936—).


SpecificationOil—Temperature 50 ± 6°C (120 ± 10°F)...................................................


5. Run engine at specifications.

SpecificationWork—Mode “M” “HD” (Heavy Duty)..........................................................Power Mode—Engine Speed “P” (Max. Power)..........................................

6. Activate bucket curl function and hold over relief.

Record pressure.

7. Adjust system relief valve (B) to the specified pressuresetting.

SpecificationSystem Relief Valve—PressureSetting 34 500—36 200 kPa (345—362

bar) (5000—5250 psi)......................................................

Turn screw in to increase pressure; turn screw out todecrease pressure.

Specification1/4 Turn of Screw Changes—Pressure 1725 kPa (17 bar) (250 psi)........................................................

If pressure does not change, circuit relief valve settingmay be low or other problem in the circuit.

8. Check power boost solenoid valve. (See procedure inthis group.)


PN=629

Tests

90252514

TX,9025,LG76 –19–28AUG97–1/2

Power Boost Solenoid Valve Test

SPECIFICATIONS


Work Mode “M” “HD” (Heavy Duty Mode)

Power Mode Engine Speed “P” (Max. Power Mode)

System Relief Valve Pressure 37 500—40 400 kPa (375—404Setting Plus Pilot Pressure bar) (5439—5860 psi)Reading

ESSENTIAL TOOLS

JT03111 (7/16-20 M 37° x 9/1618 M ORB) or AH125760 (1/2 x9/16-18 M ORB) Fitting or Male Quick Coupler (Serial No. —556935)



JT02156A Digital Pressure and Temperature Analyzer or Gauge 0—70,000 kPa (0-700 bar) (0—10,000 psi)

JT02160 Transducer 70 000 kPa (700 bar) (10,000 psi)

The power boost solenoid valve directs pilot pressure oilto the spring side of system relief valve to increase itspressure setting. The increased pressure setting will allowthe system pressure to go approximately 10% higher for aperiod of 10 seconds. Test will verify that the power boostfunction is operating.

1. Check the system relief valve first to verify its pressuresetting. (See procedure in this group.)





PN=630

Tests

90252515

TX,9025,LG76 –19–28AUG97–2/2

T76

98A

L–U

N–2

3FE

B92


T11

1911

–UN

–28O

CT

97


4. Install fitting (A) and gauge to “P” test port in pressurecontrol manifold (Serial No. —556935) or “P” test portin control valve manifold (Serial No. 556936—).




SpecificationWork—Mode “M” “HD” (Heavy Duty Mode)................................................Power Mode—Engine Speed “P” (Max. Power Mode)...............................

7. Activate bucket curl (cylinder extend) function and holdover relief.

8. Push power boost switch (on end of right control lever).

9. Record pressure.

If pressure is not to specification, check operation ofpower boost solenoid or system relief valve.

SpecificationSystem Relief Valve PressureSetting Plus Pilot—PressureReading 37 500—40 400 kPa (375—404

bar) (5439—5860 psi)...................................................

(See procedure in Group 9015-15.)


PN=631

Tests

90252516

TX,9025,LG77 –19–28AUG97–1/3

Dig Function Circuit Relief Valve Test And Adjustment (Serial No. —556935)

SPECIFICATIONS



Power Mode Engine Speed “L” (Light Duty)

Arm In and Out Circuit Relief 37 000—40 000 kPa (370—400Valves Pressure bar) (5370—5800 psi)

Bucket Curl and Dump Circuit 37 000—40 000 kPa (370—400Relief Valves Pressure bar) (5370—5800 psi)

Boom Raise and Lower Circuit 37 000—40 000 kPa (370—400Relief Valves Pressure bar) (5370—5800 psi)

Long Front Excavator Arm In 28 245—29 615 kPa (283—297Circuit Relief Valve Pressure bar) (4095—4295 psi)

Long Front Excavator Bucket 28 245—29 615 kPa (283—297Curl and Dump Circuit Relief bar) (4095—4295 psi)Valves Pressure

Long Front Excavator Arm Out 37 000—40000 kPa (370—400Circuit Relief Valve Pressure bar) (5370—5800 psi)

Long Front Excavator Boom 37 000—40000 kPa (370—400Raise and Lower Circuit Relief bar) (5370—5800 psi)Valves Pressure

1/4 Turn of Adjusting Screw 2100 kPa (21 bar) (305 psi)Changes Pressure

1/4 Turn of Long Front 2100 kPa (21 bar) (305 psi)Excavator Adjusting ScrewChanges Pressure

ESSENTIAL TOOLS

JT03111 (7/16 M 37° X 9/16 M ORB) or AH125760 (1/2 x 9/16-18M ORB) Fitting or Mail Quick Coupler (Serial No. —556935)



JT02156A Digital Pressure and Temperature Analyzer or Gauge0—70,000 kPa (0-700 bar) (0-10,000 psi)

JT02160 Transducer 70,000 kPa (700 bar) (10 000 psi)



PN=632

Tests

90252517

TX,9025,LG77 –19–28AUG97–2/3

T76

98A

M–U

N–2

3FE

B92

T76

98A

N–U

N–2

3FE

B92

A—JT03111 FittingB—LS (Load Sense) PortC—System Relief ValveD—Arm In Circuit Relief ValveE—Arm Out Circuit Relief ValveF—Bucket Curl Circuit Relief ValveG—Bucket Dump Circuit Relief ValveH—Boom Raise Circuit Relief ValveI—Boom Lower Circuit Relief Valve

The dig circuit relief valves (D—I) protect hydrauliccomponents of dig functions when control valve is inneutral.



3. Install fitting (A) and gauge to LS (load sense) port (B)in pressure control manifold.



5. Turn adjusting screw for system relief valve (C) inexactly 1/2 turn.


SpecificationWork—Mode “M” “HD” (Heavy Duty)..........................................................Power Mode—Engine Speed “L” (Light Duty).............................................

7. Operate a dig function over relief to check its circuitrelief valve (D—I). Record pressure.

SpecificationArm In and Out Circuit ReliefValves—Pressure 37 000—40 000 kPa (370—400

bar) (5370—5800 psi)....................................

Bucket Curl and Dump CircuitRelief Valves—Pressure 37 000—40 000 kPa (370—400

bar) (5370—5800 psi)..........................

Boom Raise and Lower CircuitRelief Valves—Pressure 37 000—40 000 kPa (370—400

bar) (5370—5800 psi)..........................


PN=633


Tests

90252518

TX,9025,LG77 –19–28AUG97–3/3

SpecificationLong Front Excavator Arm InCircuit Relief Valve—Pressure 28 245—29 615 kPa (283-297

bar) (4095—4295 psi)..................

Long Front Excavator Bucket Curland Dump Circuit Relief Valves—Pressure 28 245—29 615 kPa (283-297

bar) (4095—4295 psi)....................................................

Long Front Excavator Arm OutCircuit Relief Valve—Pressure 37 000—40000 kPa (370—400

bar) (5370—5800 psi).................

Long Front Excavator BoomRaise and Lower Circuit ReliefValves—Pressure 37 000—40000 kPa (370—400

bar) (5370—5800 psi).....................................

8. Turn adjusting screw for a circuit relief valve in toincrease pressure; turn screw out to decreasepressure.

Specification1/4 Turn of Adjusting ScrewChanges—Pressure 2100 kPa (21 bar) (305 psi)......................................1/4 Turn of Long Front ExcavatorAdjusting Screw Changes—Pressure 2100 kPa (21 bar) (305 psi)........................................................

9. After checking all circuit relief valves, turn adjustingscrew for system relief valve (C) out exactly 1/2 turn.


PN=634

Tests

90252519

TX,9025,LG78 –19–28AUG97–1/3

Dig Function Circuit Relief Valve Test AndAdjustment (Serial No. 556936—)

SPECIFICATIONS



Power Mode Engine Speed “L” (Light Duty)

Arm In and Out Circuit Relief 37 000—40 000 kPa (370—400Valves Pressure bar) (5370—5800 psi)

Bucket Curl and Dump Circuit 37 000—40 000 kPa (370—400Relief Valves Pressure bar) (5370—5800 psi)

Boom Raise and Lower Circuit 37 000—40 000 kPa (370—400Relief Valves Pressure bar) (5370—5800 psi)

Long Front Excavator Arm In 28 245—29 615 kPa (283—297Circuit Relief Valve Pressure bar) (4095—4295 psi)

Long Front Excavator Bucket Curl 28 245—29 615 kPa (283—297and Dump Circuit Relief Valves bar) (4095—4295 psi)Pressure

Long Front Excavator Arm Out 37 000—40000 kPa (370—400Circuit Relief Valve Pressure bar) (5370—5800 psi)

Long Front Excavator Boom 37 000—40000 kPa (370—400Raise and Lower Circuit Relief bar) (5370—5800 psi)Valves Pressure


1/4 Turn of Long Front Machine 2100 kPa (21 bar) (305 psi)Adjusting Screw ChangesPressure



JT02156A Digital Pressure and Temperature Analyzer or Gauge 0-70000 kPa (0—700 bar) (10,000 psi)




PN=635

Tests

90252520

TX,9025,LG78 –19–28AUG97–2/3

T11

0915

–UN

–08S

EP

97T

1109

16–U

N–0

8SE

P97

A—Boom Raise Circuit Relief ValveB—System Relief ValveC—Arm Out Circuit Relief ValveD—Digital Pressure and Temperature AnalyzerE—TransducerF—LS (Load Sense) PortG—Boom Lower Circuit Relief ValveH—Arm In Circuit Relief ValveI—Bucket Curl Circuit Relief ValveJ—Bucket Dump Circuit Relief Valve

The dig circuit relief valves (A, C, G—J) protect hydrauliccomponents of dig functions when control valve is inneutral.


2. Install temperature probe on reservoir-to-pump inletline. (See JT05800 Digital Thermometer Installation inthis group or use the JT02156A Digital Pressure andTemperature.)

3. Connect gauge or transducer (E) and digital pressureand temperature analyzer (D) to the LS (load sense)port test fitting (F).



5. Turn adjusting screw for system relief valve (B) inexactly 1/2 turn.


SpecificationWork—Mode “M” “HD” (Heavy Duty)..........................................................Power Mode—Engine Speed “L” (Light Duty).............................................

7. Operate a dig function over relief to check its circuitrelief valve (A, C, G—J). Record pressure.

SpecificationArm In and Out Circuit ReliefValves—Pressure 37 000—40 000 kPa (370—400

bar) (5370—5800 psi)....................................

Bucket Curl and Dump CircuitRelief Valves—Pressure 37 000—40 000 kPa (370—400

bar) (5370—5800 psi)..........................

Boom Raise and Lower CircuitRelief Valves—Pressure 37 000—40 000 kPa (370—400

bar) (5370—5800 psi)..........................

Long Front Excavator Arm InCircuit Relief Valve—Pressure 28 245—29 615 kPa (283—297

bar) (4095—4295 psi)................

Long Front Excavator Bucket Curland Dump Circuit Relief Valves—Pressure 28 245—29 615 kPa (283—297

bar) (4095—4295 psi)..................................................


PN=636


Tests

9025TX,9025,LG78 –19–28AUG97–3/3

SpecificationLong Front Excavator Arm OutCircuit Relief Valve—Pressure 37 000—40000 kPa (370—400

bar) (5370—5800 psi).................

Long Front Excavator BoomRaise and Lower Circuit ReliefValves—Pressure 37 000—40000 kPa (370—400

bar) (5370—5800 psi).....................................

8. Turn adjusting screw for a circuit relief valve in toincrease pressure; turn screw out to decreasepressure.

Specification1/4 Turn of Adjusting ScrewChanges—Pressure 2100 kPa (21 bar) (305 psi)......................................1/4 Turn of Long Front MachineAdjusting Screw Changes—Pressure 2100 kPa (21 bar) (305 psi)........................................................

9. After checking all circuit relief valves, turn adjustingscrew for system relief valve (B) out exactly 1/2 turn.

2521


PN=637

Tests

90252522

TX,9025,LG79 –19–08FEB00–1/3

Hydraulic Pump Displacement SolenoidValve Test And Adjustment

SPECIFICATIONS


Power Mode Engine Speed “I” (Low Idle Mode)


Hydraulic Pump Displacement 800—900 kPa (8—9 bar) (116—Solenoid Valve Pressure Setting 131 psi)

1/4 Turn of Adjusting Screw Approximately 69 kPa (0.69 bar)Changes Pressure (10 psi)

ESSENTIAL TOOLS

JT03456 (7/16-20 M 37° x -6 F ORFS) Adapter

T104327 (—6 M ORFS x M14-l.5 M Metric Port Thread) Adapter

51M4236 Ring

T55758 O-Ring



Gauge 0—2000 kPa (0—20 bar) (0—300 psi)





PN=638

Tests

90252523

TX,9025,LG79 –19–08FEB00–2/3

T76

54A

B–U

N–2

1NO

V91


T12

8224

–UN

–15F

EB

00

(Serial No. 559603— )

3. Remove plug. Install O-ring (D), ring (C), adapter (B),adapter (A), and gauge.

4. Start engine

SpecificationWork—Mode “M” “HD” (Heavy Duty)..........................................................Power Mode—Engine Speed “I” (Low Idle Mode)......................................

.




PN=639


Tests

9025 TX,9025,LG79 –19–08FEB00–3/3

T76

54A

D–U

N–2

1NO

V91

6. Push switch (F) on system controller two times to putcontroller into “Adjust Mode”. No. 1 green indicator lightwill be ON to indicate “Adjust Mode.” No. 2 indicatorlight will be ON for “Pump Solenoid Valve Current.”Engine speed will be at “I” (low idle mode).

7. Read pressure gauge.

8. Turn adjusting screw (E) in to decrease pressuresetting; turn adjusting out to increase pressure setting.

SpecificationHydraulic Pump DisplacementSolenoid Valve—Pressure Setting 800—900 kPa (8—9 bar)

(116—131 psi).....................

1/4 Turn of Adjusting ScrewChanges—Pressure Approximately 69 kPa (0.69 bar)

(10 psi)...............................

9. Push switch on system controller three times to returnto normal operation mode; all lights will go out.Stopping and starting engine will also return systemcontroller to normal operation mode.

2524


PN=640

Tests

90252525

TX,9025,LG80 –19–28AUG97–1/8

Load Sense Valve Differential Pressure TestAnd Adjustment

SPECIFICATIONS


Work Mode “M” “HD” (heavy duty)

Power Mode Engine Speed “P” (max. power)

(Serial No. —559602) Load 2000—2103 kPa (20—21 bar)Sense Valve Differential Pressure (290—305 psi)

(Serial No. 559603—) Load 2103—2203 kPa (21—22 bar)Sense Valve Differential Pressure (305—320 psi)

1/6 Turn of Load Sense Screw 103 kPa (1.03 bar) (15 psi)Changes Pressure

ESSENTIAL TOOLS

JT07077 Differential Pressure Gauge (0—500 psi Differential)

A—JT03216 (9/16-18 M 37° x 9/16-18 M ORB) (Parker No. 0503-6-6)or AH125760 (1/2 x 9/16-18 M ORB) Fitting (2 used) or Male QuickCoupler (Serial No. —556935)


JT02156A Digital Pressure and Temperature Analyzer or Gauge 0—70 000 kPa (0—700 bar) (0—10,000 psi)


Digital Thermometer

Load sense valve is in the pump regulator on top of mainhydraulic pump.

When differential pressure between the pump supply andload sense is too high, the controls will be overlyaggressive causing machine to be jerky and metering of afunction difficult. High differential pressure will cause thepumps to come into stroke too quickly causing boom hopwhen trying to fine grade. Machine instability or enginestalling can be other complaints. When differentialpressure is too low, hydraulic functions will be slow orinsufficient propel power. Decrease engine speed slightlyif gauge fluctuates during adjustment.

1. Remove reservoir fill cap to release air pressure. Installcap.


PN=641


Tests

90252526

TX,9025,LG80 –19–28AUG97–2/8

T76

98A

O–U

N–2

3FE

B92


T11

0918

–UN

–28O

CT

97


IMPORTANT: Avoid damage to differential pressuregauge. The higher pressure from “P”(pump supply pressure) test port mustbe connected to the HI port side ofdifferential pressure gauge. The lowerpressure from LS (load sense pressure)test port must be connected to the LOWport side of gauge.

NOTE: A differential pressure gauge or Parker SensorControl is the preferred instrument to use forsetting load sense differential pressure.

If a gauge and switch box are used, they must bechecked before starting the test. A leak in theswitch box can cause an incorrect adjustment.Because of the differences in gauge tolerance,two gauges cannot be used.

2. Install gauges or digital pressure and temperatureanalyzer transducers to “LS” test port and pressure testport “P”. For machines (Serial No. —556935), usefitting (A) or male quick coupler. If gauges are used,connect hose from “P” test port to the HI port and hosefrom “LS” test port to the LOW port on pressuredifferential gauge.

3. Install temperature probe on reservoir-to-pump inletline. (See procedure in this group.)

IMPORTANT: The oil temperature must be kept withinthe specified range to get an accuratesetting of the load sense valvedifferential pressure





PN=642


Tests

90252527

TX,9025,LG80 –19–28AUG97–3/8

T76

98A

P–U

N–2

3FE

B92


T11

0919

–UN

–08S

EP

97


CAUTION: Avoid personnel injury from theaccidental release of high pressure oil. Circuitrelief valve adjusting screw will be forced outby high pressure oil if turned out too far. Onlyturn adjusting screw out just enough to get thepressure specified.

NOTE: There are two options given, Option 1 and Option2. Please choose the option that is suitable foryou.

Option 1

1. Adjust the arm retract circuit relief valve (D) setting to12 000—12 700 kPa (120—127 bar) (1740—1842 psi).Read the pressure on gauge connected to HI port sideof differential pressure gauge.

2. Push “M” (work mode select) switch to select “HD”(heavy duty) work mode and “P” (max. power) modeswitch for engine speed.

SpecificationWork—Mode “M” “HD” (heavy duty)...........................................................Power Mode—Engine Speed “P” (max. power)..........................................

3. Remove the lock nut from stop screw (E).

4. Counting the number of turns, turn the screw in until itcontact the spool. Then slowly turn the screw in untilthe pressure is between 9300—10 700 kPa (93—107bar) (1350—1550 psi) at “P” port and is stable.

5. Read the pressure on differential pressure gauge.

Specification(Serial No. —559602) LoadSense Valve—DifferentialPressure 2000—2103 kPa (20—21 bar)

(290—305 psi).....................................................

(Serial No. 559603—) LoadSense Valve—DifferentialPressure 2103—2203 kPa (21—22 bar)

(305—320 psi).....................................................


PN=643


Tests

90252528

TX,9025,LG80 –19–28AUG97–4/8

T77

01A

Y–U

N–2

3FE

B92


T11

0920

–UN

–08S

EP

97


NOTE: For a machine with less than 100 hours, noadjustment is necessary if the pressure setting isbetween 2000—2103 kPa (20—21 bar) (290—305psi). The load sense valve spring has not yettaken a permanent set and can change.

An adjustment to the load sense valve changesthe seating between the parts and in the housing.To get an accurate adjustment, the adjustmentmust be made turning the load sense valveadjustment screw IN. Before making the finaladjustment, turn LS screw out 1/2 turn then turnthe screw IN to the final adjustment. Then afunction must be operated several times so thevalve spools and springs move and becomeseated again.

6. Adjust differential pressure to the specification.

Turn the load sense valve adjustment screw (F) in toincrease the pressure differential.

Specification1/6 Turn of Load Sense ScrewChanges—Pressure 103 kPa (1.03 bar) (15 psi).......................................

To decrease pressure differential, turn the screw out pastthe desired pressure differential setting 1/2 turn and thenturn the screw IN to the desired setting.

7. Operate a function several times and then check thedifferential pressure again.

8. Stop the engine.

NOTE: Function speed is affected if spool stop screw isnot returned to its original position.

9. Turn the arm retract valve spool stop screw out to itsoriginal position.

Adjust the arm retract circuit relief valve tospecification. (See Dig Function Circuit Relief ValveTest and Adjustment in this group.)


PN=644


Tests

90252529

TX,9025,LG80 –19–28AUG97–5/8

NOTE: If the operator feels the machine is too aggressiveor too sluggish after the above procedure hasbeen completed, the pressure gauge may be inerror. However, the differential pressure can beadjusted (fine tuned) using the followingprocedure.

10. If the machine is too aggressive, check differentialpressure using the above procedure (record thegauge reading). Then adjust the pressure to 5—10psi lower than the recorded gauge reading. Operate afunction several times and then check the differentialpressure again.

11. If the machine is too sluggish, check differentialpressure using the above procedure (record thegauge reading). Then adjust the pressure to 5—10psi higher than the recorded gauge reading. Operatea function several times and check differentialpressure again.

12. Have the operator run the machine. Check propelpower if pressure was lowered. Repeat the aboveprocedure if hydraulics remain too aggressive orsluggish.

Option 2

NOTE: Specifications and first four steps are the same forboth options.

1. Push “M” (work mode) select switch to select “HD”(heavy duty) work mode and “P” (max. power) modeswitch for engine speed.


Position the arm perpendicular to the ground so “P” portpressure is between 9300—10 700 kPa (93—107 bar)(1350—1550 psi) and stable when the boom is raisedslowly (20 in. per minute boom cylinder rod travel).


PN=645


Tests

TX,9025,LG80 –19–28AUG97–6/8

2. Read the pressure on differential pressure gauge.

Specification(Serial No. —559602) LoadSense Valve—DifferentialPressure 2000—2103 kPa (20—21 bar)

(290—305 psi).....................................................

(Serial No. 559603—) LoadSense Valve—DifferentialPressure 2103—2203 kPa (21—22 bar)

(305—320 psi).....................................................


90252530


PN=646

Tests

90252531

TX,9025,LG80 –19–28AUG97–7/8

T77

01A

Y–U

N–2

3FE

B92


T11

0920

–UN

–08S

EP

97


NOTE: For a machine with less than 100 hours, noadjustment is necessary if the pressure setting isbetween 2000—2103 kPa (20—21 bar) (290—305psi). The load sense valve spring has not yettaken a permanent set and can change.

An adjustment to the load sense valve changesthe seating between the parts and in the housing.To get an accurate adjustment, the adjustmentmust be made turning the load sense valveadjustment screw IN. Before making the finaladjustment, turn LS screw out 1/2 turn then turnthe screw IN to the final adjustment. Then afunction must be operated several times so thevalve spools and springs move and becomeseated again.

3. Adjust differential pressure to the specification.

Turn the load sense valve adjustment screw (F) in toincrease the pressure differential.

Specification1/6 Turn of Load Sense ScrewChanges—Pressure 103 kPa (1.03 bar) (15 psi).......................................

To decrease pressure differential, turn the screw out pastthe desired pressure differential setting 1/2 turn and thenturn the screw IN to the desired setting.

4. Operate a function several times and then check thedifferential pressure again.

5. Stop the engine.

NOTE: If the operator feels the machine is too aggressiveor too sluggish after the above procedure hasbeen completed, the pressure gauge may be inerror. However, the differential pressure can beadjusted (fine tuned) with the following procedure.

6. If the machine is too aggressive, check differentialpressure using the above procedure (record the gaugereading). Then adjust the pressure to 34.5—68.9 kPa(0.345—0.689 bar) (5—10 psi) lower than the recordedgauge reading. Operate a function several times andthen check the differential pressure again.


PN=647


Tests

TX,9025,LG80 –19–28AUG97–8/8

7. If the machine is too sluggish, check differentialpressure using the above procedure (record the gaugereading). Then adjust the pressure to 34.5—68.9 kPa(0.345—0.689 bar) 5—10 psi higher than the recordedgauge reading. Operate a function several times andcheck differential pressure again.

8. Have the operator run the machine. Check propelpower if pressure was lowered. Repeat the aboveprocedure if hydraulics remain too aggressive orsluggish.

90252532


PN=648

Tests

90252533

TX,9025,LG81 –19–28AUG97–1/2

Manual Bypass Pressure Reducing ValveTest And Adjustment

SPECIFICATIONS




Manual Bypass Reducing Valve 689—1000 kPa (6.89—10 bar)Pressure Setting (100—145 psi)

1/2 Turn of Adjusting Screw 138 kPa (1.4 bar) (20 psi)Changes Pressure

ESSENTIAL TOOLS

38H1029 (—4 M x —4 F x —4 M ORFS) (Parker No. 4R6LO-S) Tee

JT03455 (7/16-20 M 37° x —4 F ORFS) Adapter



JT02156A Digital Pressure and Temperature Analyzer or Gauge 0—7000 kPa (0—70 bar) (0—1000 psi)

JT02162 Transducer (35 000 kPa) (350 bar) (5000 psi)

Test is used to check the reduced pilot pressure (controlsignal) to the pump regulator load sense valve when thesystem controller manual override valve is actuated. Whenactuated, the engine speed increases to “P” (max. power)mode and the pump goes to 60—70% displacement.Engine speed and pump displacement cannot be changedusing the switches on switch panel 2.

CAUTION: Engine must not be stopped orstarted when manual bypass is actuated.

1. Install temperature probe on reservoir-to-pump inletline. (See JT05800 Digital Thermometer Installation inthis group or use the JT02156A Digital Pressure andTemperature Analyzer.)




PN=649

Tests

90252534

TX,9025,LG81 –19–28AUG97–2/2

T11

0921

–UN

–08S

EP

97

3. Install tee (D) and adapter (C) to D port. Connectgauge.





SpecificationPower Mode—Engine Speed “P” (max. power)..........................................Work—Mode “M” “HD” (heavy duty)...........................................................

6. Turn knob (A) to activate manual override (bypass)valve. Record pressure.

SpecificationManual Bypass Reducing Valve—Pressure Setting 689—1000 kPa (6.89—10 bar)

(100—145 psi)........................................

NOTE: (Serial No. 538539—) A detent was added andstyle of knob was changed on manual overridevalve.

7. Turn adjusting screw (B) in to increase pressure; turnscrew out to decrease pressure.

Specification1/2 Turn of Adjusting ScrewChanges—Pressure 138 kPa (1.4 bar) (20 psi).........................................


PN=650

Tests

90252535

TX,9025,LG82 –19–28AUG97–1/3

Swing Motor Crossover Relief Valve TestAnd Adjustment

SPECIFICATIONS


Swing Motor Crossover Relief 28 234—29 682 kPa (282—297Valve Pressure Setting bar) (4095—4305 psi)




ESSENTIAL TOOLS

JT03111 (7/16-20 M 37° x 9/16-18 M ORB) or AH125760 (1/2 x9/16-18 M ORB) Fitting or Male Quick Coupler (Serial No. —556935)


JT02156A Digital Pressure and Temperature Analyzer or Gauge 0—35 000 kPa (0—350 bar) (0—5000 psi)


Digital Thermometer

Crossover relief valves limit system pressure in swingcircuit. They protect swing components from high stressesgenerated during starting and stopping of upperstructure.Also they protect the components when control valve is inneutral.




PN=651

Tests

90252536

TX,9025,LG82 –19–28AUG97–2/3

T76

98A

Q–U

N–2

3FE

B92


T11

0922

–UN

–08S

EP

97


2. Install gauge or digital pressure and temperatureanalyzer to LS (load sense) test port.

For machines (Serial No. —556935), use fitting (A) ormale quick coupler.

For machines (Serial No. 556936—), connecttransducer (B) and digital pressure and temperatureanalyzer (C) to LS (load sense) test fitting (A).


4. Turn adjusting screw for swing torque control valve, ifequipped, in one turn. Valve setting must be higherthan swing crossover relief valve setting.

SpecificationSwing Motor Crossover ReliefValve—Pressure Setting 28 234—29 682 kPa (282—297

bar) (4095—4305 psi).........................




6. Run engine at specification.


7. Put bucket against an immovable object to stall theswing function. Check both left and right swing.



PN=652

Tests

90252537

TX,9025,LG82 –19–28AUG97–3/3

T75

76A

V–U

N–1

6AU

G91

Earlier Machine

T11

0923

–UN

–08S

EP

97

Later Machine

8. Turn screw in to increase pressure setting; turn screwout to decrease pressure setting.

Specification1/4 Turn of Adjusting ScrewChanges—Pressure 3445 kPa (34 bar) (500 psi)......................................

Front valve (C) is for left swing and rear valve (B) is forright swing.

9. Turn adjusting screw for swing torque control valve outto its original setting.


PN=653

Tests

90252538

TX,9025,GG1257 –19–17MAR95–1/3

Swing Torque Control Valve Test AndAdjustment For Long Front Machines (SerialNo. —546276)

SPECIFICATIONS

Swing Torque Control Valve 1380 kPa (13.8 bar) (200 psi)Pressure Setting less than swing crossover

pressure setting


Swing Crossover Pressure 28 234—29 682 kPa (282—297Setting bar) (4095—4305 psi)



ESSENTIAL TOOLS

JT03111 (7/16-20 M 37° x 9/16-18 M ORB) Fitting


Gauge 0—35 000 kPa (0—350 bar) (0—5000 psi)

Digital Thermometer

The swing torque control valve regulates load sense oilfrom the swing valve to the main pump regulator to controlpump output. Pump output is controlled to allow maximumflow to the swing motor without opening the swingcrossover relief valves. Swing torque control valve isadjusted so its pressure setting is less than the swingmotor crossover relief valves.

NOTE: (Serial No. 546277—) The later designed swingtorque control valve is now used for the long frontmachines. See Swing Torque Control Valve Testand Adjustment (Serial No. 546277—) in thisgroup.

1. Remove filler cap to release air pressure fromreservoir.



PN=654

Tests

90252539

TX,9025,GG1257 –19–17MAR95–2/3T

7698

AQ

–UN

–23F

EB

92

2. Install fitting (A) and gauge to “LS” (load sense) port.





5. Check the pressure setting for swing motor crossoverrelief valves. (See procedure in this group.)


SpecificationWork—Mode “M” “HD” (heavy duty)...........................................................Power Mode)—Engine Speed “P” (max. power).........................................

7. Put bucket against an immovable object. Actuatecontrol lever to full stroke to stall the swing function.Check both left and right swing. Record pressurereadings.

SpecificationSwing Crossover—PressureSetting 28 234—29 682 kPa (282—297

bar) (4095—4305 psi)......................................................

Swing Torque Control Valve—Pressure Setting 1380 kPa (13.8 bar) (200 psi)

less than swing crossoverpressure setting

.........................................



PN=655

Tests

90252540

TX,9025,GG1257 –19–17MAR95–3/3

T79

91A

B–U

N–2

7AP

R93

A—Main Control Valve D—O-Rings (2 used) F—Swing Control Valve G—Cap Screw (4 used)B—O-Rings (3 used) E—Swing Torque ControlC—Relief Valve Adjusting Valve

Screw

8. Turn relief valve adjusting screw (C) in to increasepressure setting; turn screw out to decreasepressure setting.


PN=656

Tests

90252541

TX,9025,LG84 –19–28AUG97–1/4

Swing Torque Control Valve Test AndAdjustment (Serial No. 546277—)

SPECIFICATIONS

Swing Torque Control Valve 1380 kPa (13.8 bar) (200 psi)Pressure Setting less than swing crossover

pressure setting


Swing Crossover Pressure 28 234—29 682 kPa (282—297Setting bar) (4095—4305 psi)



ESSENTIAL TOOLS

JT03111 (7/16-20 M 37° x 9/16-18 M ORB) or AH125760 (1/2 x9/16-18 M ORB) Fitting or Male Quick Coupler (Serial No. —556935)


JT02156A Digital Pressure and Temperature Analyzer or Gauge 0—35 000 kPa (0—350 bar) (0—5000 psi)


Digital Thermometer

The swing torque control valve regulates load sense oilfrom the swing valve to the main pump regulator to controlpump output. Pump output is controlled to allow maximumflow to the swing motor without opening the swingcrossover relief valves. Swing torque control valve isadjusted so its pressure setting is less than the swingmotor crossover relief valves.

NOTE: (Serial No. 546277—) The long front machinesnow use the later designed swing torque controlvalve.

1. Remove filler cap to release air pressure fromreservoir.



PN=657

Tests

90252542

TX,9025,LG84 –19–28AUG97–2/4

T76

98A

Q–U

N–2

3FE

B92


T11

0922

–UN

–08S

EP

97


2. Install gauge or digital pressure and temperatureanalyzer to the LS (load sense) test port.


For machines (Serial No. 556936—), connecttransducer (B) and digital pressure and temperatureanalyzer (C) to test fitting (A).





5. Check the pressure setting for swing motor crossoverrelief valves.

SpecificationSwing Crossover—PressureSetting 28 234—29 682 kPa (282—297

bar) (4095—4305 psi)......................................................

Swing Torque Control Valve—Pressure 1380 kPa (13.8 bar) (200 psi)

less than swing crossoverpressure setting

.....................................................

(See procedure in this group.)


Specification“M” Switch—Work Mode “HD” (heavy duty)...............................................Power Mode—Engine Speed “P” (max. power)..........................................

7. Put bucket against an immovable object. Actuatecontrol lever to full stroke to stall the swing function.Check both left and right swing. Record pressurereadings.


PN=658


Tests

90252543

TX,9025,LG84 –19–28AUG97–3/4

T11

0405

–19–

28O

CT

97


PN=659


Tests

TX,9025,LG84 –19–28AUG97–4/4

8. Turn adjusting screw (A) in to increase pressuresetting; turn screw out to decrease pressure setting.

90252544

TX,9025,LG85 –19–28AUG97–1/2

Hydraulic Control Valve Return AnticavitationCheck Valve Test

SPECIFICATIONS



Power Mode Engine Speed “I” (low idle)

Anticavitation Check Valve Return 300—500 kPa (3—5 bar) (44—73Pressure psi)

ESSENTIAL TOOLS

38H1030 (—6 M x —6 F x —6 M ORFS) (Parker No. 6R6LO-S) Tee

JT03456 (7/16-20 M 37° x —6 F ORFS) Adapter


Digital Thermometer

Gauge 0—2000 kPa (0—20 bar) (0—300 psi)

Anticavitation check valve is used to increase returnpressure in return passage of hydraulic control valvemanifold to prevent cavitation of swing and propel motorsand dig function cylinders. Test is to verify that there issufficient return pressure in manifold.


2. Heat hydraulic oil to specification.





PN=660


Tests

90252545

TX,9025,LG85 –19–28AUG97–2/2

T75

86C

H–U

N–1

6AU

G91

Earlier Machine

T11

0924

–UN

–08S

EP

97

Later Machine

4. Disconnect swing brake and gearbox lubrication andcooling flow hose (A) at gearbox. Install tee (B),adapter (C), and gauge.

NOTE: Swing brake and gearbox lubrication and coolingflow hose is connected to return passage on therear of control valve manifold.


SpecificationWork—Mode “M” “HD” (heavy duty)...........................................................Power Mode—Engine Speed “I” (low idle)..................................................

6. Record return pressure with functions in neutral.

SpecificationAnticavitation Check Valve—Return Pressure 300—500 kPa (3—5 bar) (44—73

psi)...................................

7. If pressure is not to specification, inspect anticavitationcheck valve. Replace if damaged.


PN=661

Tests

90252546

TX,902525,GG166 –19–22OCT97–1/1

Reservoir Pressure Test

T75

86B

A–U

N–1

6AU

G91

SPECIFICATIONS


Power Mode Engine Speed “I” (low idle)


Digital Thermometer

The hydraulic reservoir is pressurized by heat expansionof oil and cycling of oil in the system. Pressurizingreservoir will aid in preventing moisture and dirt fromentering hydraulic system. Pressure will also charge thehydraulic pumps.

If oil is coming from reservoir vent filter inspect the pipe(B) attached to the fitting on the inside of the reservoiropposite the vent relief valve. The pipe end is positionednear the center of the reservoir and can be observed byremoving the fill cap and looking inside reservoir. The pipeend must be tipped slightly downward to allow splashingoil to drain back to sump and not out the vent.



SpecificationOil—Temperature 50 ± 6°C (120 ± 10°F)...................................................Power Mode—Engine Speed “I” (low idle)..................................................


3. After oil has been warmed, stop engine.

4. Slowly remove hydraulic reservoir fill cap.

5. Listen for escaping air pressure from the reservoir.

6. If no pressure is heard, inspect fill cap seal. Replace ifworn.

7. Remove spin-on filter from reservoir pressure reliefvalve (A). Inspect relief valve and replace if damaged.


PN=662

Tests

90252547

TX,902525,GG183 –19–17MAR95–1/1

Oil Cooler Pressure Drop Test

SPECIFICATIONS




Oil Cooler Inlet and Outlet 280 kPa (2.8 bar) (40 psi)Pressure Drop (PressureDifference)

ESSENTIAL TOOLS

38H1034 (—20 M x —20 F x —20 M) (Parker No. 20R6LO-S)Tee (2 used)

(—20 F x —12 M ORFS) (Parker No. 20—12 TRLO-S Reducerand 20 BL-S Nut) Reducer (2 used)

JT03459 (—12 F ORFS x 7/16-20 M 37°) Adapter (2 used)


Gauge 0—2000 kPa (0—20 bar) (0—300 psi)

Digital Thermometer

Test is used to determine the flow restriction throughthe oil cooler.


2. Make test connections at oil cooler.





5. Swing upperstructure to the side. Lower boom toraise track off the ground.


SpecificationWork—Mode “M” “HD” (heavy duty)....................................................Power Mode—Engine Speed “P” (max. power)...................................

7. Fully actuate propel controller for track raised.

8. Record pressure at cooler inlet and outlet. Subtractoutlet from inlet pressure for pressure drop acrossoil cooler.

SpecificationOil Cooler Inlet and Outlet—Pressure Difference (PressureDrop) 280 kPa (2.8 bar) (40 psi)..........................................................

9. If pressure is higher than specify, back flush the oilcooler to clean it of internal restrictions. Replace oilcooler if it cannot be cleaned.


PN=663

Tests

90252548

TX,9025,LG86 –19–12JUL05–1/2

Pilot Pump Flow Test

T75

86A

G–U

N–1

6AU

G91


T11

0925

–UN

–08S

EP

97


SPECIFICATIONS



Power Mode Engine Speed "P" (max. power)

Pilot Pump Test Pressure 2760 kPa (27.6 bar) (400 psi)

Pilot Pump Minimum Flow 30.2 L/min (8 gpm)


Digital Thermometer

Flowmeter

Test will determine the condition of pilot pump (C).

The pump is loaded to a specified pressure at a givenrpm to measure pump efficiency.



3. Disconnect line at pilot filter (A) and connect toflowmeter (B) IN port.

Connect line to flowmeter OUT port and pilot filter.




5. Run engine at test specifications.

SpecificationWork—Mode “M” “HD” (heavy duty)...........................................................Power Mode—Engine Speed "P" (max. power)..........................................

6. Close flowmeter loading valve to increase pressure totest pressure.

SpecificationPilot Pump Test—Pressure 2760 kPa (27.6 bar) (400 psi) —

4206 kPa (42 bar) (610 psi)....................


PN=664


Tests

TX,9025,LG86 –19–12JUL05–2/2

7. Read flowmeter.

SpecificationPilot Pump—Minimum Flow 30.2 L/min (8 gpm)........................................

8. If flow is low, check inlet hose to pump for restriction. Ifthere is no restriction, replace pump.

90252549


PN=665

Tests

90252550


PN=666

Tests

90252551

TX,9025,DY6308 –19–11SEP97–1/5

Hydraulic Pump Test Using Flow Meter Method

SPECIFICATIONS



Power Mode Engine Speed “L” (light duty)

Hydraulic Pump Minimum Flow 220 L/min (58 gpm)at 10 340 kPa (103 bar) (1500psi)

ESSENTIAL TOOLS

A—JT03216 (9/16-18 M 37° x 9/16-18 M ORB) (Parker No.0503-6-6) or AH125760 (1/2 x 9/16-18 M ORB) Fitting or MaleQuick Coupler (Serial No. —556935)

38H1150 (—16 M ORFS) (Parker No. 16PMLO-S) Plug (2 used)

B—38H1415 (—6 F ORFS) (Parker No. 6FNL-S) Cap

D—T104327 (M14-1.5 M x 11/16-16 M ORFS) Adapter



Needle Valve

JT02156A Digital Pressure and Temperature Analyzer or Gauge0—35 000 kPa (0—350 bar) (0—5000 psi)


Flowmeter

Clamp-On Electronic Tachometer

Test indicates if the problem is in the engine,electronics, pump regulator (load sense valve andpump displacement valve), or hydraulic pump.

Do the test and make a chart of the data for thefollowing items: pump pressure, pump flow, enginespeed, temperature, and pressure at pump regulatorload sense valve “A” port.

Use the chart to determine the cause of problem:

An engine problem is indicated if pump starts todeswash at less than 9650 kPa (96.5 bar) (1400 psi)pump pressure.

An electronics, pump regulator, or pump problem isindicated if engine pulldown does not stabilize (flattenout) as pump flow is reduced.

• Check the “A” port pressure reading. The controlsignal (control pressure) from the regulator to largecontrol piston is sensed at the “A” port. If pressureincreases as pump is deswashed, a problem in thepump is indicated and electronics and pumpregulator are OK.If “A” port pressure does not increase as pump isdeswashed, an electronics or regulator problem isindicated.

• Do Hydraulic Pump Displacement Solenoid ValveTest and Adjustment. If regulated pilot pressure canbe adjusted, electronics and displacement solenoidvalve are OK. A problem is indicated in the loadsense valve.If regulated pilot pressure cannot be adjusted, apump displacement solenoid valve problem orelectronics problem is indicated.

• Check pump displacement solenoid and controlsignal from the system controller. (See procedure inSection 9015.)





PN=667

Tests

90252552

TX,9025,DY6308 –19–11SEP97–2/5

T75

86D

F–U

N–1

6AU

G91


T11

0926

–UN

–08S

EP

97


3. For machines (Serial No. —556935), install fitting(A) and hose to “P” (pump supply pressure) testport in pressure control manifold.

For machines (Serial No. 556936—), install hose to“P” (pump supply pressure) test port in control valvemanifold.

Connect hose to a needle valve. Close needlevalve.

4. Disconnect load sense line (“LS” port) at pressurecontrol manifold on machines (Serial No. —556935), or at the tee fitting (E) on the control valvemanifold on machines (Serial No. 556936—).Connect hose (C) to needle valve. Install cap (B) onfitting or tee fitting.

5. Install fitting (D) and gauge to the “A” port in thepump regulator load sense valve.


PN=668


Tests

90252553

TX,9025,DY6308 –19–11SEP97–3/5

T76

98A

R–U

N–2

3FE

B92


X98

11–U

N–2

3AU

G88

CAUTION: To avoid injury from escaping fluidunder pressure, stop engine and relieve thepressure in the system before disconnecting orconnecting hydraulic or other lines. Tighten allconnections before applying pressure.

6.

Disconnect bucket curl and bucket dump hoses. Installplugs (E). Connect flowmeter. Connect hose for bucketcurl (“A” port) to the IN port of flowmeter. Connecthose for bucket dump (B port) to the OUT port offlowmeter.



PN=669

Tests

90252554

TX,9025,DY6308 –19–11SEP97–4/5

T11

0927

–UN

–08S

EP

97

(Serial No. 556936— )

7. Check that flowmeter loading valve is open.

8. Make a chart on which to record the test data.

EXAMPLE CHART

“A” portPress Flow rpm Temp press

1200

1500

2000

2400




10. Run machine at specifications.

SpecificationWork—Mode “M” “HD” (heavy duty)....................................................Power Mode—Engine Speed “L” (light duty)........................................

11. Actuate bucket curl function and hold over relief.

12. Slowly open needle valve completely to routepump supply pressure oil to pump regulator loadsense valve (“LS” port).

Check that pressure reading for “A” port stays atzero. If reading is not zero, an electronics or pumpregulator problem is indicated.

13. Slowly close flowmeter loading valve to get thepressure readings on chart.


PN=670


Tests

9025TX,9025,DY6308 –19–11SEP97–5/5

Record the readings for pump flow, engine speed,temperature, and “A” port pressure on chart.

SpecificationHydraulic Pump—MinimumFlow at 10 340 kPa (103 bar)(1500 psi) 220 L/min (58 gpm).............................................................

EXAMPLE CHART

“A” portPress Flow rpm Temp press

1200 67 1260 120° 0

1500 64 1232 122° 650

2000 54 1225 126° 900

2400 42 1225 128° 1000

NOTE: Specifications given in example chart aretypical for a new pump.

In the example, rpm for engine pulldownreached system controller set point and pumpregulation (pump deswash to decrease flow)started between the pressure reading of 1200and 1500. Engine speed became stable(flattened out) at 1225 rpm. The systemcontroller will maintain that engine speed anddeswash the pump further as the pressureincreases.

14. Use the test record to determine the cause ofproblems.

A pump flow of less than 220 L/min (58 gpm) at 10340 kPa (103 bar) (1500 psi) is an indication ofexcessive leakage in the pump rotary group. Checkhydraulic pump case leakage flow. (See procedure inthis group.)

2555


PN=671

Tests

90252556

TX,902525,GG182 –19–17MAR95–1/2

Hydraulic Pump Test Using Cycle TimeMethod

SPECIFICATIONS

Test Course Length 20 m (65 ft)


Work Mode “M” "HD" (heavy duty)


Propel Speed High speed propel (rabbit)

Test Course Maximum Travel 20 secTime (Service Limit)


Stop Watch

Digital Thermometer

Test can be used to check pump efficiency.

1. Measure and mark the test course length.

SpecificationTest Course—Length 20 m (65 ft)..............................................................





4. Run machine through test course length several timesin both forward and reverse.

SpecificationWork—Mode “M” "HD" (heavy duty)...........................................................Power Mode—Engine Speed “P” (max. power)..........................................Propel—Speed High speed propel (rabbit).................................................

Take an average of the forward times and reverse times.

SpecificationTest Course—Maximum TravelTime (Service Limit) 20 sec.........................................................................


PN=672


Tests

TX,902525,GG182 –19–17MAR95–2/2

5. If unit is slow in one direction, check propel functionspool stop screw adjustment. (See procedure in Group9025-20.)

6. If unit is slower than time specified, do Cycle TimesTest, Pump Displacement Solenoid Valve Test andAdjustment, and Load Sense Valve DifferentialPressure Test and Adjustment. (See procedures in thisgroup.)

90252557

TX,9025,LG87 –19–28AUG97–1/3

Hydraulic Pump Case Drain Flow Test

SPECIFICATIONS




Pump Case Maximum Drain Flow 57 L/min (15 gpm)

Pump Discharge Pressure 30 000 kPa (300 bar) (4350 psi)

ESSENTIAL TOOLS

JT05690 (1-1/16-12 M 37° x —12 F ORFS) Adapter


Digital Thermometer

Flowmeter

90 mm (3-1/2 in.) OD Pin or Length of Round Bar Stock

Procedure is to check the condition of pump swashplates,valve plates, and rotating groups.



3. Disconnect pump case drain hoses at the reservoir.



PN=673

Tests

90252558

TX,9025,LG87 –19–28AUG97–2/3

T84

39B

A–U

N–2

0MA

R95


T11

0928

–UN

–08S

EP

97


4. Connect pump case drain hoses to flowmeter IN portusing the tee fitting. Install adapter (A). Connect hosefrom flowmeter OUT port to reservoir.

5. Open flowmeter loading valve.





PN=674


Tests

9025TX,9025,LG87 –19–28AUG97–3/3

T75

86D

A–U

N–1

6AU

G91

7. Put pin (D) between sprocket and track frame.


SpecificationPower Mode—Engine Speed “P” (max. power)..........................................Work—Mode“M” “HD” (heavy duty)............................................................

9. For motor being stalled, slowly push propel pedal to fulltravel and hold to operate motor at stall.

10. Actuate bucket curl function and hold over relief forone minute. Record drain flow.

SpecificationPump Case—Maximum DrainFlow 57 L/min (15 gpm)..............................................................................

11. If drain flow does not meet specification, disassemblepump and inspect.

SpecificationPump—Discharge Pressure 30 000 kPa (300 bar) (4350 psi)...................

2559


PN=675

Tests

90252560

TX,902525,GG174 –19–17MAR95–1/3

Cylinder Drift Test For Boom, Arm AndBucket

SPECIFICATIONS

Test Time 5 minutes


Bucket and Material Approximate 1500 kg (3500 lb)Test Weight

Power Mode Engine Speed Engine stopped

Cylinder Overall (Bucket to 479 mm (24.60 in.)Ground) Maximum Drift WithoutAnti-Drift Valves

Cylinder Overall (Bucket to 100 mm (4.00 in.)Ground) Maximum Drift WithAnti-Drift Valves

Boom Cylinder Maximum Drift 21 mm (0.83 in.)Without Anti-Drift Valves

Boom Cylinder Maximum Cylinder 21 mm (0.83 in.)Drift With Anti-Drift Valves

Arm Cylinder Maximum Drift 66 mm (4.00 in.)Without Anti-Drift Valves

Arm Cylinder Maximum Cylinder 66 mm (4.00 in.)Drift With Anti-Drift Valves

Bucket Cylinder Maximum Drift 19 mm (0.75 in.)Without Anti-Drift Valves

Bucket Cylinder Maximum 19 mm (0.75 in.)Cylinder Drift With Anti-DriftValves


Digital Thermometer

Test is used to check for leakage past the cylinder pistonseals and back through the control valve. Some drift,greatest during the first minute of test, is cause by trappedair in the oil.

SpecificationTest—Time 5 minutes.................................................................................





PN=676


Tests

TX,902525,GG174 –19–17MAR95–2/3


3. Fill bucket to obtain the approximate test weightspecified.

SpecificationBucket and Material—Approximate Test Weight 1500 kg (3500 lb)...............................................


90252561


PN=677

Tests

90252562

TX,902525,GG174 –19–17MAR95–3/3

T69

04A

G–U

N–0

6DE

C88

4. Extend bucket cylinder to the end of its stroke and thenretract it 20—50 mm (0.75—2.00 in.).

5. Retract arm cylinder to the end of its stroke and thenextend it 20—50 mm (0.75—2.00 in.).

6. Raise boom so bucket-to-arm pin is at the same heightas boom-to-main frame pin.

7. Stop engine.

SpecificationPower Mode—Engine Speed Engine stopped............................................

8. Measure the change in distance between bottom ofbucket and ground for the amount of drift.

SpecificationCylinder—Overall (Bucket toGround) Maximum Drift WithoutAnti-Drift Valves 479 mm (24.60 in.)...........................................................Overall (Bucket to Ground)Maximum Drift With Anti-DriftValves 100 mm (4.00 in.)............................................................................Boom Cylinder—Maximum DriftWithout Anti-Drift Valves 21 mm (0.83 in.).................................................Maximum Cylinder Drift WithAnti-Drift Valves 21 mm (0.83 in.)...............................................................Arm Cylinder—Maximum DriftWithout Anti-Drift Valves 66 mm (4.00 in.).................................................Maximum Cylinder Drift WithAnti-Drift Valves 66 mm (4.00 in.)...............................................................Bucket Cylinder—Maximum DriftWithout Anti-Drift Valves 19 mm (0.75 in.).................................................Maximum Cylinder Drift WithAnti-Drift Valves 19 mm (0.75 in.)...............................................................

If not to specification, measure the drift of each cylinder tofind circuit with high leakage. Do Steps 1—7 again andthen measure the retraction of boom and bucket cylindersand the extension of arm cylinder. Check for leakage pastthe cylinder piston seals. At the control valve, check theanti-drift valves if equipped, the circuit relief valves,anti-cavitation valves, and the valve spool.


PN=678

Tests

90252563


PN=679

Tests

90252564

TX,9025,LG89 –19–28AUG97–1/4

Swing Motor Case Drain Flow Test

T77

01B

A–U

N–2

3FE

B92

Earlier Machine



PN=680

Tests

90252565

TX,9025,LG89 –19–28AUG97–2/4

T11

0929

–UN

–08S

EP

97

Later Machine

SPECIFICATIONS



Power Mode Engine Speed “I“ (low idle)

Motor Case Maximum Leakage 5 L/min (1.3 gpm)Flow

ESSENTIAL TOOLS

D—38H1416 (—8 F ORFS) (Parker No. 8FNL-S) Cap

B—38H1415 (—6 F ORFS) (Parker No. 6FNL-S) Cap


Digital Thermometer

20 L (5 gal) Calibrated Container

Purpose of test is to check the efficiency of swingmotor. Leakage can occur between the rotating blockand valve plate or the slippers and swashplate whenparts are worn or damaged. The motor must bechecked in more than one position in order to check allpistons and the total circumference of valve plate andswashplate.

Before doing test, check that swing crossover reliefvalves and swing torque control valve (if equipped) areadjusted to specification.





3. Remove reservoir filler cap to release air pressure.

4. Disconnect swing motor drain line (C) at T port ondual solenoid block. Install cap (D) on fitting.

5. Put the end of drain hose in calibrated container.


PN=681


Tests

90252566

TX,9025,LG89 –19–28AUG97–3/4

T77

01B

A–U

N–2

3FE

B92

Earlier Machine

6.



PN=682

Tests

90252567

TX,9025,LG89 –19–28AUG97–4/4

T11

0929

–UN

–08S

EP

97

Later Machine

Disconnect swing brake release hose (A) at B port ondual solenoid block. Install cap (B) on fitting.

NOTE: An alternative to disconnecting the swingbrake release hose is to put the bucket againstan immovable object to stall the swingfunction.

7. Start engine and run at specification.

SpecificationWork—Mode “M” “HD” (heavy duty)....................................................Power Mode—Engine Speed “I“ (low idle)...........................................

8. Activate swing left function and hold at stall for oneminute.

9. Measure quantity of oil in container.

10. Activate swing right function and hold at stall forone minute.


12. Stop engine.

13. Connect swing brake release hose (A). Turnupperstructure 10—15°.

14. Repeat Steps 6—13 for several more location.

15. If leakage is more than the specification,disassemble and inspect swing motor.

SpecificationMotor Case—MaximumLeakage Flow 5 L/min (1.3 gpm).........................................................


PN=683

Tests

90252568

TX,902525,GG159 –19–17MAR95–1/2

Swing Brake And Gearbox Lubrication AndCooling Flow Test

SPECIFICATIONS


Power Mode Engine Speed "P" (max. power)

Swing Brake and Gearbox One minuteLubrication and Cooling FlowTest Time


Cooling Flow 1 L/min (1 qt/min)

ESSENTIAL TOOLS

38H1416 (—8 F ORFS) (Parker No. 8FNL-S) Cap


20 L (5 gal) Calibrated Container

Digital Thermometer

Test is to ensure that there is sufficient flow through theswing brake and gearbox for lubrication and cooling.




PN=684

Tests

90252569

TX,902525,GG159 –19–17MAR95–2/2

T75

89A

D–U

N–1

6AU

G91

Earlier Machine

T11

0930

–UN

–08S

EP

97

Later Machine

2. Disconnect swing brake and gearbox drain hose (A) atreservoir. Install cap on fitting.

3. Put end of hose in calibrated container.

4. Start engine and run at specification for one minute.

SpecificationOil—Temperature 50 ± 6°C (120 ± 10°F)...................................................Work—Mode “M” “HD” (heavy duty)...........................................................Power Mode—Engine Speed "P" (max. power)..........................................Swing Brake and GearboxLubrication and Cooling FlowTest—Time One minute...............................................................................


SpecificationCooling—Flow 1 L/min (1 qt/min)................................................................

6. If oil quantity does not meet specification, inspect orreplace orifice in inlet port of swing gearbox.


PN=685

Tests

90252570

TX,9025,DY6309 –19–11SEP97–1/2

Auxiliary Function Circuit Relief Valve TestAnd Adjustment

SPECIFICATIONS



Power Mode Engine Speed “L” (Light duty)

Auxiliary Function Circuit Relief 21 010—23 000 kPa (210—230Valve Pressure Setting bar) (3045—3335 psi)

ESSENTIAL TOOLS

JT03111 (7/16 M 37° X 9/16 M ORB) or AH125760 (1/2 x 9/16-18 MORB) Fitting or Male Quick Coupler (Serial No. —556935)


Digital Thermometer

J02156A Digital Pressure and Temperature Analyzer or Gauge 0—70000 kPa (0—700 bar) (0—10 000 psi)

JT0216D Transducer 70 000 kPa (700 bar) (10 000 psi)





PN=686

Tests

90252571

TX,9025,DY6309 –19–11SEP97–2/2

T76

98A

M–U

N–2

3FE

B92


T11

0931

–UN

–08S

EP

97


3. Install gauge or digital pressure and temperatureanalyzer to LS (load sense) test port.


For machines (Serial No. 556936—), connecttransducer (B) and digital pressure and temperatureanalyzer (C) to LS (load sense) test fitting (A).



(SeeHydraulic System Warm-Up Procedure in thisgroup.)

5. Turn adjusting screw for system relief valve (C) inexactly 1/2 turn.


SpecificationWork—Mode “M” “HD” (heavy duty)...........................................................Power Mode—Engine Speed “L” (Light duty).............................................

7. Actuate electrical switch or operate auxiliary foot pedalin one direction and hold over relief. Record pressure.

SpecificationAuxiliary Function Circuit ReliefValve—Pressure Setting 21 010—23 000 kPa (210—230

bar) (3045—3335 psi).........................

8. Turn adjustment screw or circuit relief valve in toincrease pressure; turn screw out to decreasepressure.

9. After adjustment, turn system relief adjustment screwout 1/2 turn.


PN=687

Tests

90252572

TX,902525,GG173 –19–17MAR95–1/3

Cycle Times

SPECIFICATIONS






Boom Raise (ground level to 3.6—3.8 sec typical newfull height with bucket curled,arm extended) Cycle Time

Boom Raise (ground level to 4.5 sec service limitfull height with bucket curled,arm extended) Cycle Time

Arm Out (cylinder retract) Cycle 3.6—3.8 sec typical newTime

Arm Out (cylinder retract) Cycle 4.5 sec service limitTime

Arm Ina (cylinder extend) Cycle 4.4—4.7 sec typical newTime

Arm Ina (cylinder extend) Cycle 5.5 sec service limitTime

Bucket Dump (cylinder retract) 2.6—2.7 sec typical newCycle Time

Bucket Dump (cylinder retract) 3.2 sec service limitCycle Time

Bucket Curl (cylinder extend) 3.8—4.1 sec typical newCycle Time

Bucket Curl (cylinder extend) 4.8 sec service limitCycle Time

Swing Left Or Right—3 16.0 sec typical newRevolutions From RunningStart (bucket curled, armretracted) Cycle Time

Swing Left Or Right—3 23.0 sec service limitRevolutions From RunningStart (bucket curled, armretracted) Cycle Time

Track Raised—3 Revolutions 16.5 sec typical newFrom Running Start (check inforward and reverse) CycleTime

Track Raised—3 Revolutions 24.0 sec service limitFrom Running Start (check inforward and reverse) CycleTimeaSetting of arm cylinder restrictor affects the cycle time.


PN=688


Tests

TX,902525,GG173 –19–17MAR95–2/3

SPECIFICATIONS

Propel 20 m (65 ft) (check in 12.0—15.5 sec typical newforward and reverse) CycleTime

Propel 20 m (65 ft) (check in 20.0 sec service limitforward and reverse) CycleTime


Stop Watch

Tape Measure


90252573


PN=689

Tests

90252574

TX,902525,GG173 –19–17MAR95–3/3

T79

18A

O–U

N–1

1JA

N93

Boom Position

T79

18A

P–U

N–1

1JA

N93

Arm, Bucket And Swing Position

T71

60A

L–U

N–0

3JA

N90

Propel 3-Revolution Position

See Diagnose Malfunctions in Group 9025-15 for dig andswing functions or Group 9020-15 for propel function ifcycle times are greater than the specifications.

SpecificationOil—Temperature 50 ± 6°C (120 ± 10°F)...................................................Work—Mode “M” “HD” (heavy duty)...........................................................Power Mode—Engine Speed “P” (max. power)..........................................Propel—Speed High speed propel (rabbit).................................................Test Course—Length 20 m (65 ft)..............................................................Boom Raise (ground level to fullheight with bucket curled, armextended)—Cycle Time 3.6—3.8 sec typical new.......................................Cycle Time 4.5 sec service limit..................................................................Arm Out (cylinder retract)—CycleTime 3.6—3.8 sec typical new.....................................................................Cycle Time 4.5 sec service limit................................................................

Arm In1 (cylinder extend)—CycleTime 4.4—4.7 sec typical new.....................................................................Cycle Time 5.5 sec service limit..................................................................Bucket Dump (cylinder retract)—Cycle Time 2.6—2.7 sec typical new...........................................................Cycle Time 3.2 sec service limit..................................................................Bucket Curl (cylinder extend)—Cycle Time 3.8—4.1 sec typical new...........................................................Cycle Time 4.8 sec service limit..................................................................Swing Left Or Right—3Revolutions From Running Start(bucket curled, arm retracted)—Cycle Time 16.0 sec typical new.................................................................Cycle Time 23.0 sec service limit................................................................Track Raised—3 RevolutionsFrom Running Start (check inforward and reverse)—CycleTime 16.5 sec typical new...........................................................................Cycle Time 24.0 sec service limit................................................................Propel 20 m (65 ft) (check inforward and reverse)—CycleTime 12.0—15.5 sec typical new.................................................................Cycle Time 20.0 sec service limit................................................................

1Setting of arm cylinder restrictor affects the cycle time.


PN=690

Tests

90252575

TX,9025,SS2005 –19–17MAR95–1/2

Cycle Times For Long Front

SPECIFICATIONS






Boom Raise (ground level to full 7.0 secheight with bucket curled, armextended) Cycle Time

Arm Out (cylinder retract) Cycle 7.4 secTime

Arm Ina (cylinder extend) Cycle 8.2 secTime

Bucket Dump (cylinder retract) 2.3 secCycle Time

Bucket Curl (cylinder extend) 2.3 secCycle Time

Swing Left or Right—3 27.0 secRevolutions from Running Start(bucket curled, arm retracted)Cycle Time

Track Raised—3 Revolutions 16.5 sec typical newfrom Running Start (check inforward and reverse) Cycle Time

Track Raised—3 Revolutions 24.0 sec service limitfrom Running Start (check inforward and reverse) Cycle Time

Propel 20 m (65 ft) (check in 12.0—15.5 sec typical newforward and reverse) Cycle Time

Propel 20 m (65 ft) (check in 20.0 sec service limitforward and reverse) Cycle TimeaSetting of arm cylinder restrictor affects the cycle time


Stop Watch

Tape Measure



PN=691

Tests

90252576

TX,9025,SS2005 –19–17MAR95–2/2

T81

94A

G–U

N–1

4MA

R94

Boom Position

T77

25A

H–U

N–0

3JU

N92

Arm Position

IMPORTANT: Because of the extra length, the boomand arm can be damaged if cycle timesare faster (less) than the times given.Never adjust the spool stop screws toget cycle times faster than the timesgiven.

See Diagnose Malfunctions in Group 9025-15 for dig andswing functions or Group 9020-15 for propel function.

SpecificationOil—Temperature 50 ± 6°C (120 ± 10°F)...................................................Work—Mode “M” “HD” (heavy duty)...........................................................Power Mode—Engine Speed “P” (max. power)..........................................Propel—Speed High speed propel (rabbit).................................................Test Course—Length 20 m (65 ft)..............................................................Boom Raise (ground level to fullheight with bucket curled, armextended)—Cycle Time 7.0 sec..................................................................Arm Out (cylinder retract)—CycleTime 7.4 sec................................................................................................Arm In1 (cylinder extend)—CycleTime 8.2 sec................................................................................................Bucket Dump (cylinder retract)—Cycle Time 2.3 sec......................................................................................Bucket Curl (cylinder extend)—Cycle Time 2.3 sec......................................................................................Swing Left or Right—3Revolutions from Running Start(bucket curled, arm retracted)—Cycle Time 27.0 sec....................................................................................Track Raised—3 Revolutionsfrom Running Start (check inforward and reverse)—CycleTime 16.5 sec typical new...........................................................................Cycle Time 24.0 sec service limit................................................................Propel 20 m (65 ft) (check inforward and reverse)—CycleTime 12.0—15.5 sec typical new.................................................................Cycle Time 20.0 sec service limit................................................................

1Setting of arm cylinder restrictor affects the cycle time


PN=692

Tests

90252577

TX,9025,DY6310 –19–11SEP97–1/1

TM Worksheet 1 Of 7—690E LC Excavator

CUSTOMER’S NAME____________________________ Follow all safetyprecautions listed in test procedures. Adjust Low andHigh Idle using System Controller.

MACHINE SERIAL NO. ______________________

ENGINE SPEED ADJUSTMENT

TM Specs Actual Readings Reset to Group

Low idle range 820—880 rpm 9010-20

High idle stop screw 2175—2225 rpm

NOTE: Auto idle and economy are controlled by thesystem controller and are not adjustable.

PILOT PRESSURE REGULATING VALVE TEST AND ADJUSTMENT

Pressure change per one shim: Approximately 20 psi

Work mode: “HD”; Power mode (engine speed): “L”

Pilot System 435—610 psi 9025-25

SYSTEM RELIEF VALVE TEST AND ADJUSTMENT

1/4 turn = Approximately 250 psi

Work mode: “HD”; Power mode (engine speed): “P”

Gauge in “P” port (Serial 5000—5250 psi 9025-25No. —556935) Fig. 3(Serial No. 556936—) Fig. 8

POWER BOOST TEST

Not adjustable, check power boost solenoid or system relief valve if not to specification.


Gauge in “P” port 5439—5860 psi 9025-25

PROPEL MOTOR CROSSOVER RELIEF VALVE TEST AND ADJUSTMENT

0.005 in. Shim = 100 psi approximate; 0.020 in. Shim = 500 psi approximate


Set system relief valve higher than propel crossover by turning the system relief IN exactly 1/2 turn.

Stall each track with a 3-1/2 in. diameter solid steel pin.

Pressure Setting Forward Right Forward Left

Gauge in “LS” port Fig. 3 or 4946—5831 psi 9020-25Fig. 8

Reverse Right Reverse Left

Reset system relief valve exactly 1/2 turn OUT now, or continue to Dig Function Circuit Relief Valve Test and Adjustment.


PN=693

Tests

90252578

TX,9025,DY6311 –19–11SEP97–1/1


ARM CYLINDER RESTRICTOR ADJUSTMENT

Group

Work mode: “EC”; Power mode (engine speed): “E”. 9025-20

Actuate Arm-in function to full stroke. As arm travels through its arc, the arm must not hesitate. Turn arm cylinder restrictor (A, Fig. 1 or A,Fig. 8) in to eliminate hesitation. (See last page of TM Worksheet for art.) (Serial No. 546277—556935) Arm cylinder restrictor is now locatedin the arm regenerative valve.

NOTE: If arm-in cycle time is too slow, arm cylinderrestrictor may be turned in too far.

DIG FUNCTION CIRCUIT RELIEF VALVE TEST AND ADJUSTMENT

1/4 turn = Approximately 305 psi.

Work mode: “HD”; Power mode (engine speed): “L”

Turn system relief valve IN one turn so setting is higher than circuit relief valve setting. Install gauge in “LS” port.

TM Specs Actual Reading Reset to Group

Bucket Curl Head End 5370—5800 psi 9025-25

Bucket Dump Rod End

Arm In Head End

Arm Out Rod End

Boom Raise Head End

Boom Lower Rod End

Long Front Machine Specifications

Bucket Curl Head End 4095—4295 psi 9025-25

Bucket Dump Rod End

Arm In Head End

Arm Out Rod End 5370—5800 psi

Boom Raise Head End

Boom Lower Rod End

Turn system relief valve OUT 1 turn (to original setting).


PN=694

Tests

90252579

TX,9025,DY6313 –19–12SEP97–1/1


LOAD SENSE VALVE DIFFERENTIAL PRESSURE ADJUSTMENT

1/4 turn = Approximately 75 psi.

Hydraulic Oil Temp: 50 ± 6°C (120 ± 10°F)


TM Specs Actual Reading Reset to Group

Pressure Differential between 290—305 psi 9025-25“LS” and “P”

LS Valve Adjustment Screw (A, Fig. 2 or A, Fig. 7); Displacement Adjustment Screw (B, Fig. 2 or B, Fig. 7) (See last page of TM Worksheetfor art.)

NOTE: Use accurate test equipment. Leaking switchboxes, or use of gauges with too much value

between gauge lines will result in impropersetting.

Adjust Load Sense Differential Pressure

When differential pressure between the pump supply and load sense is too high, the controls will be overly aggressive causing machine to bejerky and metering of a function difficult. High differential pressure will cause the pumps to come into stroke too quickly causing boom hopwhen trying to fine grade. Machine instability can be another complaint. When differential pressure is too low, hydraulic functions will be slow.Decrease engine speed slightly if gauge fluctuates during adjustment.

Make test connections to ports “P” and “LS” 9025-25

CAUTION: Do not back relief adjust screw allthe way out. Personal injury could resultfrom release high pressure oil or flying part.

Adjust arm-in circuit relief valve (B, Fig. 3 or B, Fig. 6) to 1740—1842 psi

Work Mode: “HD”; Power Mode (engine speed): “P”

Turn arm spool stop screw (C, Fig. 3 or C, Fig. 6) IN to get 1350—1550 psi at “P” port

NOTE: When using the differential pressure gauge,both ends must be connected. “LS” isconnected to low side and “P” is connected tohigh side.

Adjustment must be made turning load sensevalve adjustment screw in for final adjustment.Turn LS screw out 1/2 turn then in for finaladjustment.

Adjust load sense valve adjustment screw (A, Fig. 2 or A, Fig. 7) to desired load sense differential.

Record load sense differential pressure (normal 290—305 psi).

Return spool stop screw to its original position. (Approximately 12 turns OUT from touching spool).

Tighten lock nut on spool stop screw

Adjust arm circuit relief valve to 5365—5655 psi.


PN=695

Tests

90252580

TX,9025,DY6314 –19–12SEP97–1/1


PUMP DISPLACEMENT SOLENOID VALVE ADJUSTMENT

Group


Remove plug and install test fitting (A, Fig. 4 or A, Fig. 9) and gauge. 9025-25

Start the engine.

Push switch on system controller two times to put controller into adjust mode.

No. 1 green indicator light will be on “Adjust Mode.”

No. 2 red indicator light will be on “Pump Solenoid Valve Current” (No. 3 and No. 7 lights will also be on).

Read the gauge.

Turn adjustment screw (B, Fig. 4 or B, Fig. 7) in to decrease pressure or out to increase pressure to 116—131 psi.

Push switch on system controller three times to return to normal operation.

MANUAL BYPASS REDUCING VALVE ADJUSTMENT


CAUTION: Engine must not be stopped orstarted when system controller manualoverride (bypass) valve is actuated.

Install tee (D, Fig. 5 or D, Fig. 10) and adapter (C). 9025-25

Mode switch: “HD”; Power mode (engine speed): “P”

Open manual override valve (A, Fig. 5 or A, Fig. 10).

Adjust pressure reducing valve screw (B, Fig 5 or B, Fig. 10) to 100—145 psi.

SWING MOTOR CROSSOVER RELIEF VALVE TEST AND ADJUSTMENT



NOTE: For machine with swing torque control valve,see procedure in technical manual.

TM Specs Actual Reading Reset to

Gauge in “LS” port 4095—4305 psi Right Swing 9025-25Left Swing

PROPEL SPEED CYCLE TIME

Track raise—3 revolutions from a running start—high speed propel

Actual Reading

New 16.5—24.0 sec. 9020-25


PN=696

Tests

90252581

TX,9025,GG1261 –19–17MAR95–1/1


T76

55A

D–U

N–2

1NO

V91

PROPEL BRAKE PRESSURE REDUCING VALVE ADJUSTMENT

Group



Propel speed: High speed propel (Rabbit)

Disconnect line (A); leave open. 9020-25

Install fittings (B and C) and gauge.

Operate propel at stall in forward and reverse.

Turn adjusting screw (D) for propel brake pressure reducing valve to 435—1015 psi.

NOTE: If pressure does not go to zero with propel inneutral, check the orifice behind plug (E).


PN=697

Tests

90252582

TX,9025,DY6315 –19–12SEP97–1/1

TM Worksheet 6 Of 7—690E LC Excavator Art (Serial No. —556935)

T77

18B

B–1

9–09

MA

R92


PN=698

Tests

90252583

TX,9025,DW1378 –19–31JUL97–1/1

TM Worksheet 7 Of 7—690E LC Excavator Art (Serial No. 556936—)

T11

0932

–UN

–29O

CT

97


PN=699

Tests

90252584


PN=700

Section 9031Air Conditioning SystemContents

Page Page

Group 05—Theory Of Operation High Refrigerant Pressure Switch . . . . . . . .9031-25-14Heater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9031-05-1 Leak Testing . . . . . . . . . . . . . . . . . . . . . . . .9031-25-15Air Conditioning System . . . . . . . . . . . . . . . .9031-05-2 Hoses and Tubing Inspection . . . . . . . . . . .9031-25-15Air Conditioning Circuit . . . . . . . . . . . . . . . . .9031-05-4Air Conditioning Fan . . . . . . . . . . . . . . . . . . .9031-05-6Receiver/Dryer . . . . . . . . . . . . . . . . . . . . . . .9031-05-8Expansion Valve . . . . . . . . . . . . . . . . . . . . .9031-05-10Compressor Relief Valve. . . . . . . . . . . . . . .9031-05-11

Group 10—System Operational ChecksAir Conditioning System (Serial No. —

541550) . . . . . . . . . . . . . . . . . . . . . . . . . . .9031-10-1Air Conditioning Operational Checks . . . . . . .9031-10-1Visual Inspection Of Components . . . . . . . . .9031-10-1System Operating Checks. . . . . . . . . . . . . . .9031-10-4System Performance Checks . . . . . . . . . . . .9031-10-6Air Conditioning Electrical Circuit Checks . . .9031-10-8

Group 15—Diagnostic InformationAir Conditioning Electrical (SN —541550) . . .9031-15-1Air Conditioning Component Location (Serial

No. —541550) . . . . . . . . . . . . . . . . . . . . . .9031-15-3

9031Group 20—AdjustmentsAir Conditioning System (Serial No. —

541550) . . . . . . . . . . . . . . . . . . . . . . . . . . .9031-20-1Refrigerant (R-12) Cautions . . . . . . . . . . . . .9031-20-1Check And Add Compressor Oil . . . . . . . . . .9031-20-2Gauge Set Installation Procedure . . . . . . . . .9031-20-3Refrigerant Recovery . . . . . . . . . . . . . . . . . .9031-20-4Evacuate The System . . . . . . . . . . . . . . . . . .9031-20-5Charge The System . . . . . . . . . . . . . . . . . . .9031-20-6Add Refrigerant To The System . . . . . . . . . .9031-20-7Check And Adjust Compressor Belt

Tension . . . . . . . . . . . . . . . . . . . . . . . . . . .9031-20-8

Group 25—TestsAir Conditioning System (Serial No. —

541550) . . . . . . . . . . . . . . . . . . . . . . . . . . .9031-25-1Refrigerant (R-12) Cautions . . . . . . . . . . . . .9031-25-1Air Conditioning System Test . . . . . . . . . . . .9031-25-2Operating Pressure Diagnostic Chart . . . . . .9031-25-5Expansion Valve

Operating Test. . . . . . . . . . . . . . . . . . . . .9031-25-10Bench Test and Adjustment. . . . . . . . . . .9031-25-11

Low Refrigerant Pressure Switch . . . . . . . .9031-25-13


PN=1

Contents

9031


PN=2

Group 05Theory Of Operation

9031051

TX,9031,GG1252 –19–06MAR95–1/1

Heater Operation

TP

2999

8–U

N–0

1JA

N94

00—Heater 4—Cap Screw (7 used) 6—Screw (2 used) 8—Lock Washer (7 used)1—Control Panel and Cable 5—Clamp (2 used) 7—Lock Washer (2 used) 9—Washer (7 used)3—Air Duct

The flow of coolant is from the rear of engine, to theheater valve, through the heater, and then to the waterpump.


PN=703

Theory Of Operation

903105

2

TX,9031,MD83 –19–06MAR95–1/2

Air Conditioning System Operation

T75

85A

F–1

9–30

JUL9

1

NOTE: (Serial No. —541550) Factory air conditioningno longer available.

The compressor draws low pressure gas from theevaporator and compresses it into high pressure gas.Increasing the pressure of refrigerant causes its boilingpoint to rise to a temperature higher than the outsideair temperature.

As the high pressure gas flows through the condenser,the engine fan draws air through the condenser corewhich cools the refrigerant. Cooling the refrigerantcauses it to condense and leave the condenser as ahigh pressure liquid.

The high pressure liquid flows into the receiver/dryerwhere moisture and contaminants are removed. The

receiver/dryer is also a reservoir that stores excessrefrigerant. A sight glass is mounted in the top ofreceiver/dryer. Bubbles can be seen in the sight glasswhen the system refrigerant is low.

The refrigerant flows from the receiver/dryer to theexpansion valve. The expansion valve is a variableorifice used to cause a pressure and temperature dropin the refrigerant and regulate flow into the evaporator.Lowering the pressure of the refrigerant lowers itsboiling point. As the liquid refrigerant flows into theevaporator, warm cab air flowing through theevaporator core causes the refrigerant to vaporize.Cab air is cooled and dehumidified.


PN=704


Theory Of Operation

TX,9031,MD83 –19–06MAR95–2/2

A gas filled sensing bulb connected to a diaphragm inthe expansion valve is used to control refrigerant flowthrough the evaporator. The sensing bulb is fastenedto the evaporator outlet tube and senses thetemperature of the refrigerant at the evaporator outlet.The sensing bulb and outlet tube are insulated withtape to keep outside air temperature from affectingoperation of the expansion valve. If too muchrefrigerant is flowing into the evaporator, the liquidrefrigerant will still be evaporating as it leaves theevaporator causing a low temperature at the

evaporator outlet. The low temperature causes theexpansion valve variable orifice to decrease in size,restricting refrigerant flow. If the evaporatoroutlet-temperature is too warm, the orifice will increasein size allowing more refrigerant into evaporator. Ifevaporator temperature becomes too high or low thethermostat switch will interrupt current flow tocompressor clutch coil, stopping system operation untiltemperature becomes normal. When thermostat switchstops system operation, maintenance is usuallyrequired to correct a problem.

9031053


PN=705

Theory Of Operation

903105

4

TX,9031,MD86 –19–13JUL92–1/2

Air Conditioning Circuit Operation

T76

10A

C–1

9–26

SE

P91


PN=706


Theory Of Operation

9031055

TX,9031,MD86 –19–13JUL92–2/2

Air conditioner circuit contains: 10-amp monitor fuseF6, 20-amp blower and air conditioner clutch fuse F13,blower relay, blower motor, blower switch, airconditioner switch, compressor clutch indicator light,compressor relay, thermostat switch, high/low pressureswitch, compressor clutch coil.

Current from blower and air conditioning clutch fuseflows to blower relay and air conditioner compressorrelay. Current from 10-amp monitor fuse flows toblower relay and air conditioner switch. When blowerswitch is turned to low, current flows through blowerswitch making a ground for blower relay coil energizingit. Current flows through blower relay, motor and tworesistors to ground, motor runs in low speed. Whenblower switch is turned to medium, blower relay coil isgrounded through blower switch, current flows throughblower motor and one resistor to ground, motor runs inmedium speed. When blower switch is turned to high,current flows through blower relay and motor throughblower switch to ground, motor runs at high speed.

With blower switch ON in low, medium or high and airconditioner switch ON, current flows throughcompressor relay, clutch indicator light and blowerswitch to ground illuminating indicator light andenergizing compressor relay.

The thermostat switch prevents evaporator freeze-up.Thermostat switch is closed during normal operationallowing current to flow to high/low pressure switchand compressor clutch coil to ground, engagingcompressor clutch. If temperature in evaporator goesbelow specified range, thermostat switch opens,de-energizing compressor clutch until evaporatortemperature is within specification. Thermostat switchthen closes, energizing compressor clutch.

The high/low pressure switch is closed when it is in thesystem (system pressure above 207 kPa 30 psi), but isopen when exposed to ambient air pressure. High/lowpressure switch will open if the air conditioning systemloses its refrigerant charge. The switch opens to stop

current flow to the compressor clutch coil preventingcompressor engagement. The high/low switch islocated on the outlet side of the receiver/dryer.

The high/low pressure switch is closed unless systempressure goes above 2647 kPa (384 psi). If amalfunction or line restriction causes pressure toincrease above switch setting, the switch will openstopping current flow to the compressor clutch coil.

The compressor relief valve is a direct acting reliefvalve mounted on compressor outlet tube. If systempressure exceeds 3100 kPa (450 psi) relief valve willopen with a loud popping sound. Whenever thecompressor relief valve opens a malfunction usuallyexists and should be corrected.

With the engine running, blower switch ON, airconditioner switch ON, the compressor clutch isengaged and the compressor operates. Refrigerant ina gaseous state enters the compressor and iscompressed into a high pressure, high temperaturegas.

High pressure, high temperature gas flows into thecondenser where the engine fan draws ambient airthrough the condenser coils, cooling the gas. As thegas is cooled it condenses into a high pressure liquid.

High pressure liquid flows through the receiver/dryerwhere it is filtered and moisture is removed.

High pressure liquid flows through expansion valveorifice where pressure is reduced allowing refrigerantto boil and vaporize as it enters the evaporator as acold low pressure gas. Vaporization continues as theblower fan blows air across evaporator coils. Air beingblown across evaporator coils becomes cold and coolsthe operators compartment.

Low pressure warm gas enters the compressor to startthe cycle again.


PN=707

Theory Of Operation

903105

6

TX,9031,MD84 –19–13JUL92–1/1

Air Conditioning Fan Operation

T76

10A

B–1

9–26

SE

P91

Current from 10-amp Monitor fuse flows to blowerrelay coil, current from 20-amp Blower fuse flows toblower relay contact. When blower switch is turned toLOW, ground is provided for blower relay coil throughblower switch, closing relay contacts sending current tomotor. Ground for motor is through two resistors whichreduce voltage to motor, causing it to run at lowspeed. When blower switch is turned to MEDIUM

speed, ground for motor is provided through oneresistor and through blower switch, the resistorreduces voltage causing motor to run at mediumspeed. When blower switch is turned to HIGH speed,ground for motor is provided through blower switchdirectly to ground without going through any resistors.Full voltage is available to motor, causing it to run athigh speed.


PN=708

Theory Of Operation

9031057


PN=709

Theory Of Operation

903105

8

903105,SS29 –19–03MAY93–1/2

Receiver/Dryer Operation

T59

61A

I–U

N–0

8NO

V88

A—Inlet PortB—Sight GlassC—Outlet PortD—Pickup TubeE—FilterF—DesiccantG—Strainer

The receiver/dryer is a reservoir to store excess liquidrefrigerant in the system. Excess refrigerant is required fortwo reasons:

Outside air temperature and humidity have an effect onthe minimum quantity of refrigerant required in the systemfor the air conditioner to operate at maximum efficiency.The higher the temperature and humidity, the morerefrigerant required in the system. More refrigerant isrequired due to the expansion valve opening fartherallowing more refrigerant into the low pressure side of thesystem.

Refrigerant hoses allow a small amount of refrigerant tomigrate through their walls. Extra refrigerant stored in thesystem allows for a longer period of time before additionalrefrigerant is needed.

The receiver/dryer also contains two filters (E) and adesiccant (F) between the filters. The filters remove solidmaterials which could be generated by a compressorfailure, debris left in the system due to improper serviceprocedures, or particles caused by corrosion of metalparts due to moisture and acids in the system (alsocaused by improper service procedures).

Desiccant is used to absorb moisture. If too muchmoisture gets into the system, the desiccant may not beable to absorb it all. When moisture is combined withrefrigerant oil, a sludge is formed. This sludge does notpermit moving parts to be adequately lubricated. Whenmoisture is combined with refrigerant, hydrofluoric andhydrochloric acids are formed. These acids are verycorrosive to metal surfaces and leakage will eventuallydevelop. If the air conditioning system is left open for aperiod of time or if the plugs are removed from thereceiver/dryer, the desiccant will also absorb moisturefrom the air. Evacuating the system will not removemoisture from the desiccant.



PN=710

Theory Of Operation

903105,SS29 –19–03MAY93–2/2

A sight glass is installed in the receiver/dryer outlet port. Ifthe refrigerant level is low, a steady stream of gasbubbles will be present in the liquid flowing from thereceiver/dryer. These gas bubbles can be seen in thesight glass and are an indication that the system needscharging. However, bubbles may be present when thecompressor clutch first engages but must disappear aftera few seconds. If the sight glass is clear, the systemeither has a sufficient charge or is completely discharged.

9031059


PN=711

Theory Of Operation

90310510

903105,SS30 –19–13JUL92–1/1

Expansion Valve Operation

T59

61A

K–U

N–0

8NO

V88

A—Sensing BulbB—Equalizer LineC—DiaphragmD—Inlet PassageE—OrificeF—Valve SeatG—SpringH—Outlet Passage

The expansion valve is used to regulate the amount ofrefrigerant flowing into the evaporator. Since morerefrigerant can be vaporized by warm moist air than cooldry air, the expansion valve adjusts flow to the maximumamount that can be vaporized in the evaporatordepending upon the heat and humidity in the air.

The expansion valve is also an orifice used to cause apressure drop in the liquid refrigerant to lower its boilingpoint, causing the refrigerant to vaporize as it is heated bythe air flowing through the evaporator. Since heat isrequired to vaporize a liquid, the heat is removed from theair and added to the refrigerant.

The expansion valve is controlled by a gas filled sensingbulb (A) connected to a diaphragm (C). The sensing bulbis fastened to the evaporator outlet line and senses thetemperature of the refrigerant leaving the evaporator. Thebulb and line are wrapped with insulating tape to keepoutside air temperature from affecting valve operation. Iftoo much refrigerant is flowing through the evaporator, theliquid refrigerant will still be evaporating as it leaves theevaporator, causing a low temperature at the evaporatoroutlet. The low temperature causes the gas pressure inthe sensing bulb to decrease. Spring (G) moves valveseat (F) closer to orifice (E), reducing the refrigerant flow.If outlet temperature is too warm, gas pressure in sensingbulb will increase, causing diaphragm (C) to move valveseat (F) away from orifice (E), increasing refrigerant flow.

If the expansion valve sensing bulb does not make goodcontact with the evaporator outlet line, or if the insulatingtape is missing, frost will form on the evaporator outletline. Frost forms because the sensing bulb will not becooled to the actual line temperature. This will keep theexpansion valve open too far and the refrigerant will stillbe evaporating as it leaves the evaporator, cooling theline to less than 0°C (32°F).

An external equalizer line (B) is connected to theevaporator outlet line to transmit evaporator outletpressure to the spring side of the diaphragm. Using anexternal equalizer line causes a more stable operation ofthe valve.


PN=712

Theory Of Operation

903105,SS32 –19–13JUL92–1/1

Compressor Relief Valve Operation

The compressor relief valve is a direct acting pressurelimiting valve. If a malfunction in the system occursthat would cause high pressure, such as a restrictedline, the valve will open at 3100 ± 380 kPa (31 ± 3.8bar) (450 ± 55 psi) and remain open until pressuredrops to below the valve setting.

If the relief valve opens, a loud popping noise will beheard. Some oil may also be lost from the system.Correct any condition that would cause the valve toopen.

90310511


PN=713

Theory Of Operation

90310512


PN=714

Group 10System Operational Checks

TX,9031,GG1255 –19–06MAR95–1/1

Air Conditioning System (Serial No. —541550)

NOTE: (Serial No. —541550) Factory air conditioning nolonger available.

9031101

TX,9031,RP576 –19–16SEP92–1/1

Air Conditioning Operational Checks

This procedure is designed so the mechanic can makea quick check of the system using a minimum amountof diagnostic equipment. If you need additionalinformation, read Theory of Operation (Group9031-05).

The engine or other major components must be atoperating temperature for some checks.

Locate system check in the left column and readcompletely, following this sequence from left to right.Read each check completely before performing.

At the end of each check, if no problem is found, thatcheck is complete. When a problem is indicated,additional checks or repair information will be

given.T.M. Group or CTM number required for repairwill be given. If verification is needed, you will be givennext best source of information:

(System Operational Checks)

(Diagnostic Information)

(Adjustments)

(Tests)

CTM (Component Technical Manual)

T.M. (Technical Manual)

– – –1/1

1 Visual Inspection Of Components


PN=715


– – –1/1

All Lines And Hoses Engine OFF.

Inspect all lines and hoses.

Are lines and hoses straight, NOT kinked or worn from rubbing on other machine partsor "weather checked"?

Are hose and line connections clean NOT showing signs of leakage, such as oil ordust accumulation at fittings?

All hose and line clamps must be in place and tight. Clamps must have rubber insertsor cushions in place to prevent clamps from crushing or wearing into hoses or lines.


NO: Reposition hoses orlines and tighten orreplace clamps. Tightenfittings or replace O-ringsin fittings. Replace hosesor lines as required.

903110

2 – – –1/1

Air ConditionerCompressor

Engine OFF.

Inspect compressor.

Is compressor drive belt tight? Specification is 19 mm (0.75 in.) deflection with 90 N(20 lb force) midway between pulleys.

Is belt in good condition, NOT frayed, worn or glazed?

Is compressor belt pulley in good condition, NOT worn or grooved?

Are compressor mounting brackets in good condition, NOT bent or broken?

Are compressor mounting bracket cap screws tight?

Is compressor pulley aligned with engine pulleys, NOT worn or grooved?

Are electrical connections to compressor clutch clean and tight? Is wiring tocompressor in good condition?


NO: Repair or replacecomponents as required.

– – –1/1

Condenser Check Engine OFF.

Inspect condenser cores.

Is condenser core free of dirt or debris?

Does condenser show signs of leakage, dust accumulation or oily areas?

Are condenser fins straight, NOT bent or damaged?

Inspect engine fan.

Are fan blades in good condition, NOT worn, bent, broken or missing?


NO: Clean, repair orreplace condenser core.Replace engine fan.


PN=716


– – –1/1

Evaporator Core Engine OFF.

Inspect core.

Are fins straight?

Is evaporator core free of dirt and debris?


NO: Repair, replace orclean evaporator.

– – –1/1

Thermostat SwitchSensing Tube

Engine OFF.

Inspect thermostat switch sensing tube.

Is sensing tube straight, NOT kinked or broken?

Is sensing tube inserted into evaporator core and secured in place?


NO: If sensing tube iskinked, replacethermostat switch.

NO: If tube is positionedin evaporator incorrectly,re-route.

9031103

– – –1/1

Expansion Valve Check Engine OFF.

Inspect expansion valve.

Is insulation tape covering sensing bulb and tightly wound around bulb and evaporatoroutlet line?

Is sensing bulb line straight, NOT kinked or broken?


NO: If insulating tape ismissing or loose, replace.

NO: If sensing bulb line iskinked or broken, replaceexpansion valve.


PN=717


– – –1/1

Heater Shut-Off Valve Engine OFF.

Close heater shut-off valve located on engine.

Run engine at operating temperature. Operate heater fan on high speed.

Move heater temperature control to HOT.

Does heater valve move freely through operating range?

Run blower fan on high speed.

Does hot air come through heater outlets?

Move heater temperature control to COLD.

Is cooler air coming from heater outlets?


NO: If air coming fromheater outlets is hot orwarm all the time, replaceshut-off valve.

– – –1/1

Cab Door And WindowSeals

Open and close door and windows. Inspect seals.

Do door and windows contact seals evenly?

Are seals in position and in good condition?


NO: Adjust door andwindows to close againstseals properly. Replaceseals as necessary.

903110

4 – – –1/1

2 System Operating Checks

– – –1/1

Blower Motor Check Key switch ON.

Engine OFF.

Turn blower switch to LOW, MEDIUM and HIGH.

Does fan have three speeds?

Does air exit from ducts?


NO: Check F6 Monitorfuse and F13 Airconditioner fuse, blowerrelay, blower switch,blower motor and wiringto blower motor.


PN=718


– – –1/1

Blower Relay Check Key switch ON.

Engine OFF.

Turn blower switch to LOW then OFF.

Does relay "Click" as switch is turned from OFF to LOW?


NO: Check F13 Blowerfuse and F6 Monitor fuse,blower switch, blower andwiring.

– – –1/1

Compressor Relay Check Key switch ON.

Engine OFF.

Turn blower switch on LOW.

Push air conditioning switch.

Does compressor relay “Click”?

Does compressor clutch solenoid “Click”?


NO: Check F6 Monitorfuse, air conditionerswitch. compressor relay,thermostat switch lowpressure switch, highpressure switch,compressor clutchsolenoid and wiring.

9031105

– – –1/1

Low Pressure SwitchCheck

Key switch ON. Blower switch on LOW.

Engine OFF.

Disconnect low pressure switch wiring leads.

Does compressor clutch solenoid “click” when wiring leads are disconnected?

Reconnect low pressure switch wiring leads to harness.

Does compressor clutch solenoid “click” as wiring leads are reconnected?

YES: Check Complete.

NO: If compressor clutchsolenoid does not click asspecified, low pressureswitch is failed. Replacelow pressure switch.

– – –1/1

High Pressure SwitchCheck

Key switch ON. Blower switch on LOW.

Engine OFF.

Disconnect high pressure switch wiring leads.

Reconnect high pressure switch wiring leads to harness.

Does compressor clutch solenoid “click” when wiring leads are disconnected?


NO: If compressor clutchsolenoid does not “click”as specified, highpressure switch is failed.Replace high pressureswitch.


PN=719


– – –1/1

Low And High PressureValve Schrader ValveCheck

Engine OFF.

Remove low and high pressure switches from line. (Schrader valves are located underpressure switch to prevent system from discharging when switch is removed.)

Does refrigerant leak from schrader valve?

YES: Discharge airconditioning system andreplace schrader valve.(See Recover andRecycle RefrigerantGroup 9031)

NO: Check complete.

– – –1/1

Compressor ClutchCheck

Engine OFF.

Key switch ON.

Blower switch on LOW.

Push air conditioner switch to ON.

Does Compressor clutch “click” as switch is pushed?


NO: Replace compressorclutch.

903110

6 – – –1/1

3 System Performance Checks

– – –1/1

System PerformanceCheck

NOTE: Perform VISUAL INSPECTION and OPERATING CHECKS in this group priorto evaluating air conditioning system performance.

Turn blower switch to HIGH position.

Push air conditioner switch to ON.

Move heater control to COLD position, and close heater shut-off valve.

Start engine and run at fast idle for 5 minutes.

Measure air temperature at condenser inlet. Measure air temperature at air ducts incab.

If condenser inlet air (ambient) temperature is below 27°C (80°F), duct air temperaturemust be below 13°C (55°F).

If condenser inlet air temperature is above 27°C (80°F), duct air temperature must be14—17°C (25—30°F) below condenser inlet air temperature.

YES: Operation issatisfactory, SystemOperational Checkout iscomplete.

NO: Continue check.


PN=720


– – –1/1

Receiver/Dryer Check

T6493AO –19–28FEB89

Position controls as in System Performance Check.

After starting engine observe receiver/dryer sight glass.

Bubbles may be present when compressor clutchengages but must disappear after a few seconds.


NO: Go to RechargeSystem in Group9031-20.

– – –1/1

Expansion Valve Check Is expansion valve outlet line free of frost?

Is insulating tape wound tightly around sensing bulb and outlet line and is tape in goodcondition?


NO: Inspect clampholding bulb on sensingline. Clean bulb and line.Reapply insulating tape.Go to Expansion ValveBench Test andAdjustment in Group1830.

9031107

– – –1/1

Evaporator Check Remove seat and covers over evaporator.

Is ice forming on evaporator core?

Is fan motor failing or fan blades damaged?

Is thermostat switch sensing tube properly positioned?

Is heater temperature control misadjusted or damaged?

Is evaporator core plugged with dirt?

Is evaporator drain tube plugged or damaged?

YES: Repair as needed.

NO: Go to ThermostatSwitch Bench Test orExpansion Valve BenchTest in Group 1830.

– – –1/1

Evaporator HousingDrain Check

Remove bottom guard from underside of cab.

Is water dripping on cab floor?

Is drain tube plugged, cracked or misrouted?

Is evaporator housing or drain tray broken?

Is drain tube connected to drain?

YES: Repair or replaceas needed.

NO: Air ConditioningOperation Checkoutcomplete.


PN=721


– – –1/1

4 Air Conditioning Electrical Circuit Checks

Circuit is powered by 10-amp Monitor fuse and 20-amp Blower and A/C fuse.

– – –1/1

Air Conditioner BlowerSwitch Check

T7584AH –UN–29JUL91

Disconnect harness from switch.

Turn switch to LOW.

Measure continuity in blower switch connector from D toC terminal.

Turn switch to MEDIUM.

Measure continuity from D to C and A terminals.

Turn switch to HIGH.

Measure continuity from D to C and B terminals.

Is continuity measured as specified?

YES: Switch is OK.Check wiring harness.

NO: Replace blowerswitch.

903110

8

– – –1/1

Air Conditioner SwitchCheck

T7584AG –UN–29JUL91

Push air conditioner switch to ON position.

Measure continuity in air conditioner switch connectorbetween terminals C and B.

Is continuity measured?


NO: Replace switch.

– – –1/1

Air Conditioner BlowerMotor Check

T7584AI –UN–29JUL91

Disconnect harness from blower switch.

Key switch ON.

Connect a jumper wire between harness connectorterminals C and D.

Does blower motor run at low speed?

YES: Blower motor is OK.Check blower switch.

NO: Check wiringharness. Replace blowermotor if harness is OK.


PN=722


– – –1/1

Low Pressure SwitchCheck

T7584AJ –UN–29JUL91


Measure continuity across switch connector terminals #1and #2.

Does Ohmmeter read continuity?


NO: Switch is failed orsystem needs recharging.

– – –1/1

High Pressure SwitchCheck

T7584AK –UN–29JUL91


Measure continuity across switch terminals #2 and #3.

Does Ohmmeter read continuity?


NO: Switch is failed orsystem pressure is toohigh.

9031109

– – –1/1

Compressor Clutch CoilCheck

T7585AG –19–06AUG91

Disconnect harness from clutch.

Connect battery voltage to red wire terminal incompressor connector. Ground black wire terminal.

Does clutch coil “click”?

YES: Check wiringharness.

NO: Replace clutch coil.

– – –1/1

Blower Fan Relay Check

T7585AH –19–06AUG91

Disconnect harness from relay.

Connect battery voltage to terminal #86. Ground terminal#85.

Does relay “click”?

Measure continuity between terminals #30 and #87.


YES: Relay is OK. Checkwiring harness.

NO: Replace relay.


PN=723


– – –1/1

Compressor Relay Check

T7585AH –19–06AUG91

Disconnect harness from relay.

Connect battery voltage to terminal #86. Ground terminal#85.

Does relay “click”?

Measure continuity between terminals #30 and #87.


YES: Relay is OK. Checkwiring harness.

NO: Replace relay.

90311010


PN=724

Group 15Diagnostic Information

9031151

TX,9031,RP604 –19–06MAR95–1/2

Diagnose Air Conditioning ElectricalMalfunctions (Serial No. —541550)

NOTE: Diagnose malfunction charts are arranged frommost probable and simplest to verify, to leastlikely, more difficult to verify. Remember thefollowing steps when troubleshooting a problem:

• Step 1. Operational Checkout to verifysymptom.

• Step 2. Diagnose Malfunctions Chart forpossible problems of symptoms.

• Step 3. Electrical Operational Checkout to verifyproblem.

• Step 4. Tests


Air Conditioning System Does F6 Monitor Fuse or F13 Blower Fuse Replace fuse.Not Operate

Blower switch See Air Conditioner Blower SwitchCheck, Group 9031-10.

Fan motor See Air Conditioner Fan MotorCheck, Group 9031-10.

Blower Relay See Blower Relay Check, Group9031-10

Air Conditioner Switch See Air Conditioner Switch Check,Group 9031-10

Compressor Relay See Compressor Relay Check,Group 9031-10

Thermostat switch See Air Conditioner ThermostatSwitch Check, Group 9031-10.

Low pressure switch See Air Conditioner Low PressureSwitch Check, Group 9031-10.

High pressure switch See Air Conditioner High PressureSwitch Check, Group 9031-10.


PN=725



TX,9031,RP604 –19–06MAR95–2/2


Compressor clutch coil See Compressor Clutch Coil Check,Group 9031-10.

Wiring harness Check wiring harness.

903115

2


PN=726


TX,9031,RP605 –19–06MAR95–1/1

Air Conditioning Component Location (Serial No. —541550)T7724AC –19–03SEP97


PN=727


903115

4


PN=728

Group 20Adjustments

TX,9031,GG1253 –19–06MAR95–1/1



9031201

903120,SS1 –19–16SEP92–1/1

Refrigerant (R-12) Cautions

CAUTION: DO NOT allow liquid refrigerant(R-12) to contact eye or skin. Liquidrefrigerant (R-12) will freeze eye or skin oncontact. Wear goggles, gloves and protectiveclothing.

If liquid refrigerant (R-12) contacts eye orskin, DO NOT rub the area. Splash largeamounts of COOL water on affected area. Goto a physician or hospital immediately fortreatment.

DO NOT allow refrigerant (R-12) to contactopen flames or very hot surfaces such aselectric welding arc, electric heating elementand lighted smoking materials. Refrigerant(R-12), exposed to high temperature, formsphosgene gas.

Inhaling toxic phosgene gas may result inserious illness or death. Phosgene gas has

an odor like new mown hay or green corn. Ifyou inhale phosgene gas, go to a physicianor hospital immediately for treatment.

DO NOT heat refrigerant (R-12) over 52°C(125°F) in a closed container. Heatedrefrigerant (R-12) will develop high pressurewhich can burst the container.

Keep refrigerant (R-12) containers away fromheat sources. Store refrigerant (R-12) in acool place.

DO NOT handle damp refrigerant (R-12)container with your bare hands. Skin mayfreeze to container. Wear gloves.

If skin freezes to container, pour COOLwater over container to free the skin. Go to aphysician or hospital immediately fortreatment.


PN=729

Adjustments

903120

2

TX,9031,RP601 –19–13JUL92–1/1

Check And Add Compressor Oil

IMPORTANT: The compressor takes a special 525viscosity oil that has "specialadditives" which give bettercompressor life.

If complete system was flushed toremove contamination, the fullcharge of oil 326 mL (11 fl oz) mustbe added to the system.

1. Remove compressor. Drain the oil from the suctionport and record amount of oil.

2. If 90—240 mL (3—8 fl oz) was drained from theoriginal compressor, add 180 mL (6 fl oz) of new oilback into the compressor.

3. If more than 240 mL (8 fl oz) was drained from theoriginal compressor, add 180 mL (6 fl oz) of new oilback into the compressor. Replace receiver/dryer toremove excess oil from the system.

4. If less than 90 mL (3 fl oz) was drained from theoriginal compressor, flush all components of thesystem. Replace the receiver/dryer and add 330 mL(11 fl oz) of new oil back into the system.

5. When installing a compressor that has beendisassembled and reassembled with no oil charge,

add an extra 30 mL (1 fl oz) to the amountsspecified in steps 2, 3 or 4.

6. When installing a new or remanufacturedcompressor, drain the oil. Replace with new oil persteps 2, 3 or 4.

7. If components of the system were drained andflushed, add 330 mL (11 fl oz) to the compressor.

8. After adding proper amount of oil, rotate thecompressor shaft four or five times to insure properlubrication of the compressor seal.

IMPORTANT: DO NOT add any more oil thannecessary or maximum cooling willbe reduced.

9. When servicing individual components, determinethe oil charge needed using following chart:

Component Oil Charge

Condenser 30 mL (1 fl oz)

Evaporator 60 mL (2 fl oz)

Receiver/Dryer 10 mL (0.4 fl oz)


PN=730

Adjustments

9031203TX,9031,RP606 –19–16SEP92–1/1

Air Conditioning Gauge Set InstallationProcedure

T74

84A

Z–U

N–0

4AP

R91

A—High Pressure SwitchB—Red HoseC—Blue HoseD—High Pressure Relief Valve

ESSENTIAL TOOLS

D18018KD Air Conditioning Test Equipment Kit

JT02022 Refrigerant Recovery System

JT02020 or JT02021 Refrigerant Recovery/Recycling System

CAUTION: Do not remove high pressure reliefvalve (D). Air conditioning system willdischarge rapidly causing possible injury.

1. Remove cap from low-side test port.

2. Close both valves on Air Conditioning Gauge Set.

3. Remove high pressure switch (A) and connect redhose (B).

4. Connect blue hose (C) to low-side test port.

5. Connect yellow hose to Recovery System.


PN=731

Adjustments

TX,1830,QQ1103 –19–06MAR95–1/1

Refrigerant Recovery

T74

84B

C–U

N–0

8AP

R91

903120

4

A—Red HoseB—Blue HoseC—Yellow Hose

ESSENTIAL TOOLS


JT02022 Refrigerant Recovery System

JT02020 or JT02021 Refrigerant Recovery/Recycling System

NOTE: Run the air conditioning system for three minutesto help in the recovery process. Turn airconditioning system off before proceeding withrecovery steps.

1. Connect air conditioning gauge set. (See installationprocedure in this group.)

2. Connect yellow hose (C) to a Refrigerant RecoverySystem or a Refrigerant Recovery/Recycling System.


PN=732

Adjustments

9031205

TX,1830,QQ1104 –19–16SEP92–1/2

Evacuate The System

T65

97B

D–U

N–2

5OC

T88


ESSENTIAL TOOLS


D05267ST Vacuum Pump

IMPORTANT: DO NOT run compressor whileevacuating.


2. Connect yellow hose of gauge set to a vacuum pump.

3. Start vacuum pump.

4. Open low-side and high-side valves.

5. Evacuate system until low-side gauge registers 98 kPa(980 mbar) (29 in. Hg) vacuum.

If 98 kPa (980 mbar) (29 in. Hg) vacuum cannot beobtained in 15 minutes, test the system for leaks. (SeeLeak Testing, 9031-25). Correct any leaks.

NOTE: The vacuum specifications listed are for sea levelconditions. Subtract 3.4 kPa (34 mbar) (1 in. Hg)from 98 kPa (980 mbar) (29 in. Hg) for each 300m (1000 ft) elevation above sea level.

6. When vacuum is 98 kPa (980 mbar) (29 in. Hg), closelow-side and high-side valves. Turn vacuum pump off.

7. If the vacuum decreases more than 3.4 kPa (34 mbar)(1 in. Hg) in 5 minutes, there is a leak in the system.

8. Repair leak.

9. Start the vacuum pump.

10. Open low-side and high-side valves.

11. Evacuate system for 30 minutes after 98 kPa (980mbar) (29 in. Hg) vacuum is reached.

12. Close low-side and high-side valves. Stop vacuumpump.


PN=733


Adjustments

TX,1830,QQ1104 –19–16SEP92–2/2

13. Charge the system. (See procedure in this group.)

903120

6

TX,1830,QQ1105 –19–16SEP92–1/1

Charge The System

T65

97B

E–U

N–2

5OC

T88


ESSENTIAL TOOLS


D05271ST Charging Cylinder

IMPORTANT: DO NOT run compressor while chargingthe system if using a charging cylinder.


2. Connect gauge set yellow hose to charge cylinder "HI"valve or container of R-12. If using container of R-12,invert container so valve is on bottom.

3. Open valve completely on charging cylinder of R-12container.

4. If using a charging cylinder, add 2.3 kg (5 lb) of R-12through the high-side valve. Close high-side valve.

5. If using containers of R-12, open high-side valve untilpressure stops rising. Close valve.

6. Open low-side valve until pressure stops rising.

7. Start engine and run at 1/2 speed.

IMPORTANT: Regulate low-side valve to keeplow-side pressure reading below 275kPa (2.8 bar) (40 psi) when chargingsystem. This will assure refrigerantenters system as a vapor. Too muchliquid entering the compressor candamage internal parts.


PN=734

Adjustments

9031207

TX,1830,QQ1106 –19–13JUL92–1/1

Add Refrigerant To The System

T65

97B

B–U

N–2

5OC

T88


ESSENTIAL TOOLS



2. Connect yellow hose to a container of R-12.

3. Loosen yellow hose fitting at gauge set. Open valve onrefrigerant container for a few seconds to purge airfrom hose. Tighten fitting.

4. Open valve on refrigerant container. Invert thecontainer.

5. Start engine and run at approximately 2000 rpm.

IMPORTANT: Be sure that refrigerant enters systemonly as a vapor. Too much liquidentering the compressor can damageinternal parts. Regulate the valve on thecontainer or low-side valve so that thelow-side reading will not exceed 275kPa (2.8 bar) (40 psi). This will assurethat refrigerant in the hose hasvaporized before entering thecompressor.

6. Open low-side valve just enough to keep pressure lessthan 275 kPa (2.8 bar) (40 psi).

7. Add refrigerant until bubbles disappear from sightglass.

8. Weigh the container of R-12.

9. Add an additional .23 kg (.5 lb) of refrigerant.


PN=735

Adjustments

TX,1830,QQ1112 –19–16SEP92–1/1

Check And Adjust Compressor Belt Tension


Belt Tension Gauge

IMPORTANT: NEVER over tighten belt. Overtightening may cause belt corddamage and excessive load onbearings.

1. Run engine for five minutes. Stop the engine, thenimmediately check tension using a belt tensiongauge. Measure strand tension or deflection at apoint halfway between pulleys.

2. Belt must deflect 19 mm (0.75 in.) at 90 N (20 lbforce). If not, allow belt to cool for 8—10 minutes.

IMPORTANT: Force to adjust belt must be appliedto front of compressor housing onlyto prevent damage to compressor.

3. Loosen compressor mounting cap screws. Applyforce to front of compressor housing to tighten belt.Tighten cap screws.

4. Repeat Steps 1 and 2 to check belts.

903120

8


PN=736

Group 25Tests

TX,9031,GG1253 –19–06MAR95–1/1



9031251

903125,SS10 –19–16SEP92–1/1

Refrigerant (R-12) Cautions

CAUTION: DO NOT allow liquid refrigerant(R-12) to contact eye or skin. Liquidrefrigerant (R-12) will freeze eye or skin oncontact. Wear goggles, gloves and protectiveclothing.

If liquid refrigerant (R-12) contacts eye orskin, DO NOT rub the area. Splash largeamounts of COOL water on affected area. Goto a physician or hospital immediately fortreatment.

DO NOT allow refrigerant (R-12) to contactopen flames or very hot surfaces such aselectric welding arc, electric heating elementand lighted smoking materials. Refrigerant(R-12), exposed to high temperature, formsphosgene gas.

Inhaling toxic phosgene gas may result inserious illness or death. Phosgene gas has

an odor like new mown hay or green corn. Ifyou inhale phosgene gas, go to a physicianor hospital immediately for treatment.

DO NOT heat refrigerant (R-12) over 52°C(125°F) in a closed container. Heatedrefrigerant (R-12) will develop high pressurewhich can burst the container.

Keep refrigerant (R-12) containers away fromheat sources. Store refrigerant (R-12) in acool place.

DO NOT handle damp refrigerant (R-12)container with your bare hands. Skin mayfreeze to container. Wear gloves.

If skin freezes to container, pour COOLwater over container to free the skin. Go to aphysician or hospital immediately fortreatment.


PN=737

Tests

903125

2 903125,SS11 –19–16SEP92–1/3

Air Conditioning System Test

SPECIFICATIONS

15°C (60°F) Condenser Inlet Air 7—76 kPa (0.07—0.76 bar) (1—Temperature Low Side Pressure 11 psi)

15°C (60°F) Condenser Inlet Air 690—900 kPa (6.9—9.0 bar)Temperature High Side Pressure (100—130 psi)

21°C (70°F) Condenser Inlet Air 10—86 kPa (0.1—0.86 bar)Temperature Low Side Pressure (1.5—12.5 psi)


27°C (80°F) Condenser Inlet Air 7—117 kPa (0.7—1.17 bar) (1—Temperature Low Side Pressure 17 psi)


32°C (90°F) Condenser Inlet Air 21—124 kPa (0.21—1.24 bar)Temperature Low Side Pressure (3—18 psi)


38°C (100°F) Condenser Inlet Air 38—145 kPa (0.38—1.45 bar)Temperature Low Side Pressure (5.5—21 psi)


43°C (110°F) Condenser Inlet Air 62—165 kPa (0.62—1.65 bar)Temperature Low Side Pressure (9—24 psi)




PN=738

Tests

9031253903125,SS11 –19–16SEP92–2/3

T65

97B

A–U

N–0

8NO

V88



Air Conditioning Gauge Set

Thermometer

1. Connect air conditioning gauge set. (See AirConditioning Gauge Set Installation Procedure inGroup 9031-20.)

2. Start engine and run at fast idle.

3. Turn temperature control switch to the maximumcooling position.

4. Turn blower switch to high speed.

5. Check sight glass in receiver/dryer.

6. Run unit for at least 5 minutes.

7. Measure air temperature at condenser air inlet and atair ducts in air conditioning unit.

If condenser inlet air temperature is below 27°C (80°F),duct air temperature must be below 13°C (55°F). Ifcondenser inlet air temperature is above 27°C (80°F),duct air temperature must be at least 14°C (25°F)below condenser inlet air temperature.



PN=739

Tests

903125

4

903125,SS11 –19–16SEP92–3/3

T65

97B

A–U

N–0

8NO

V88

A—High-Side Pressure (Red Hose)B—Low-Side Pressure (Blue Hose)C—Yellow Hose

8. Observe low-side pressure (B) and high-side pressure(A) on gauges.

9. Compare pressure readings to the pressure shown inspecifications.

Specification15°C (60°F) Condenser Inlet AirTemperature—Low Side Pressure 7—76 kPa (0.07—0.76 bar)

(1—11 psi).................

High Side Pressure 690—900 kPa (6.9—9.0 bar)(100—130 psi)

......................................

21°C (70°F) Condenser Inlet AirTemperature—Low Side Pressure 10—86 kPa (0.1—0.86 bar)

(1.5—12.5 psi).................


..................................


(1—17 psi).................


..................................


(3—18 psi).............


..............................


(5.5—21 psi).............


..............................


(9—24 psi).............


..............................

Use the Operating Pressure Diagnostic Chart in this groupto diagnose the malfunction.


PN=740

Tests

9031255

T59,5969CL –19–23APR93–1/5

Operating Pressure Diagnostic Chart

Low Side High SidePressure Pressure Sight Glass Problem Solution

Low Low Clear Loss of R-12 Leak in system. Do leak test. Repairleak. Add R-12. Normal migrationthrough hoses. Add R-12.

Low Low or Normal Bubbles Loss of R-12 Leak in system. Do leak test. Repairleak. Add R-12 in this group.

Normal migration through hoses. AddR-12 in this group.

Restriction in system: Inspect for bent, kinked, or dentedBetween compressor and lines. Feel lines for a temperatureCondensor. change. Discharge system. InspectInside condenser. and backflush each component.Between condenser andreceiver/dryer.Inside receiver/dryer.

Low Low or Normal Clear Blower motor running too slow. Check for motor shaft binding ordefective electrical connections.

Evaporator core dirty or air flow Clean evaporator and straighten fins.through evaporator restricted.

Temperature control switch Do Temperature Control Switchmalfunction. Operating Test in Group 25.

Do Temperature Control Switch BenchTest and Adjustment in Group 25.

Expansion valve stuck closed. Do Expansion Valve Operating Test inGroup 25.

Do Expansion Valve Bench Test andAdjustment in Group 25.

Restriction in system: Inspect for bent, kinked, or dentedBetween receiver/dryer and lines. Feel lines for a temperatureexpansion valve. change. Discharge system. InspectAt expansion valve. and backflush each component.Inside evaporator.Between evaporator andcompressor.



PN=741

Tests

903125

6

T59,5969CL –19–23APR93–2/5


Low Low or Normal Clear Moisture in system. Discharge, flush, purge, evacuate, andcharge the system (Group 20).

Low High Clear or Bubbles Restriction in system: Inspect for bent, kinked or dentedBetween compressor and lines. Feel lines for a temperaturecondenser. change. Discharge system. InspectInside condenser. and backflush each component.Between condenser andreceiver/dryer.Inside receiver/dryer.Between receiver/dryer andexpansion valve.

Normal Normal Clear Heater valve not closing. Close heater shut-off valve on engineblock or clamp heater hoses shut.

Expansion valve sensing bulb not Check evaporator outlet line orproperly insulated or not making compressor inlet line for frost. If frostgood contact with evaporator forms, remove sensing bulb andoutlet tube. inspect sensing bulb and line for dirt

and corrosion. Clean bulb and lines.Install clamp to fasten bulb tightly toside of outlet line. Install insulatingtape to completely cover bulb andoutlet line.

Expansion valve malfunction. Check evaporator outlet line orcompressor inlet for frost. If frostforms, do Expansion Valve OperatingTest in this group.

Temperature control switch Do Temperature Control Switchmalfunction. Operating Test in this group.

Moisture in system (intermittent Discharge, flush, purge, evacuate, andcooling below 27°C [80°F] charge the system (Group 1830).ambient.)

Normal Normal Occasional Loss of R-12 Leak in system. Do leak test. RepairBubbles leak. Add R-12 in this group.

Normal migration through hoses. AddR-12 in this group.

Air in system. Discharge, purge, evacuate, andcharge the system (Group 20).



PN=742

Tests

9031257

T59,5969CL –19–23APR93–3/5


Normal High Clear Restricted air flow through Inspect for debris. Straighten fins. Docondenser or radiator. Radiator Air Flow Test. (See procedure

in Group 9010-25.)

Expansion valve sensing bulb not Remove sensing bulb and inspect bulbproperly insulated or not making and line for dirt and corrosion. Cleangood contact with evaporator bulb and line. Install clamp to fastenoutlet tube. bulb tightly to side of outlet line. Install

insulating tape to completely coverbulb and outlet line.

Overcharge of refrigerant. Start engine and run at fast idle.Operate air conditioner at maximumcooling. Release refrigerant fromlow-side of system until bubblesappear in sight glass. Add 0.7 kg (1.5lb) of refrigerant through low-sidevalve.

Expansion valve malfunction. Do Expansion Valve Operating Test.(See procedure in Group 25.)

Restriction in system: Inspect for bent, kinked, or dentedBetween compressor and lines. Feel lines for a temperaturecondenser. change. Discharge system. InspectInside condenser. and backflush each component.Between condenser andreceiver/dryer.Inside receiver/dryer.

Normal High Bubbles Restriction in system: Inspect for bent, kinked, dented, orBetween compressor and pinched lines. Feel lines for acondenser. temperature change. DischargeInside condenser. system. Inspect and backflush eachBetween condenser and component.receiver/dryer.Inside receiver/dryer.

High Low Clear Compressor belt loose. Tighten belt.

Compressor clutch slipping. Check for battery voltage atcompressor clutch with clutchengaged. Clean electrical connectionsor replace relay.

Inspect and repair clutch. (Seeprocedure in Group 1830).



PN=743

Tests

903125

8

T59,5969CL –19–23APR93–4/5


High Low Clear Compressor failure. Test compressor efficiency. (Seeprocedure in Group 1830.)

High Normal Clear Expansion valve sensing bulb not Check evaporator outlet line andproperly insulated or not making compressor inlet line for frost. Removegood contact with evaporator sensing bulb and inspect bulb and lineoutlet tube. Expansion valve for dirt and corrosion. Clean bulb andstuck open. line. Do Expansion Valve Operating

Test in this group. Install clamp tofasten bulb tightly to side of outlet line.Install insulating tape to completelycover bulb and outlet line.

High High Clear Restricted air flow through Inspect for debris. Straighten fins. Docondenser or radiator. Radiator Air Flow Test. (See procedure

in Group 9010-25.)

Expansion valve sensing bulb not Check evaporator outlet line andproperly insulated or not making compressor inlet line for frost. Removegood contact with evaporator sensing bulb and inspect bulb and lineoutlet tube. for dirt and corrosion. Clean bulb and

line.

Expansion valve stuck open. Do Expansion Valve Operating Test inthis group. Install clamp to fasten bulbtightly to side of outlet line. Installinsulating tape to completely coverbulb and outlet line.

Overcharge of refrigerant. Start engine and run at fast idle.Operate air conditioner at maximumcooling. Release refrigerant fromlow-side of system until bubblesappear in sight glass. Add 0.7 kg (1.5lb) of refrigerant through low-sidevalve.

Restriction in system: Inspect for bent, kinked, dented, orBetween compressor and pinched lines. Feel lines for acondenser. temperature change. DischargeInside condenser. system. Inspect and backflush eachBetween condenser and component.receiver/dryer.Inside receiver/dryer.

High High Bubbles Air in system. Discharge, purge, evacuate, andcharge the system. (See procedure inGroup 20).

Restriction in system: Inspect for bent, kinked, dented, orBetween compressor and pinched lines. Feel lines for acondenser. temperature change. DischargeInside condenser. system. Inspect and backflush eachBetween condenser and component.receiver/dryer.Inside receiver/dryer.


PN=744


Tests

9031259

T59,5969CL –19–23APR93–5/5

T66

09A

B–1

9–28

FE

B89


PN=745

Tests

903125,SS14 –19–04AUG92–1/2

Expansion Valve Operating Test

T65

97B

A–U

N–0

8NO

V88

90312510




1. Connect air conditioning gauge set. (See AirConditioning Gauge Set Installation Procedure inGroup 9031-20.)

2. Remove insulating tape from expansion valve sensingbulb.

903125,SS14 –19–04AUG92–2/2

T66

19A

V–U

N–2

5OC

T88

3. Remove clamp to remove sensing bulb (A).

4. Start engine and run at fast idle.

5. Turn blower switch on high. Turn temperature controlswitch to maximum cooling. Turn heat/cool vent toCOOL.

6. Warm sensing bulb in the hand for 1 minute. Notelow-side pressure.

7. Cool sensing bulb in ice water. Note low-side pressure.

If low-side pressure decreases when sensing bulb iscooled, expansion valve is operating. If low-sidepressure does not decrease, do Expansion ValveBench Test and Adjustment in this group.

8. Before fastening sensing bulb to evaporator outlet line,make sure line and bulb are not corroded. Fastensensing bulb to the side of the line with clamp. Installinsulating tape to completely cover sensing bulb andline.


PN=746

Tests

903125,SS16 –19–03MAY93–1/3

Expansion Valve Bench Test And Adjustment

ESSENTIAL TOOLS

JT05419 Air Conditioning Service Fitting Kit



90312511

903125,SS16 –19–03MAY93–2/3

T84

070

–UN

–06D

EC

88A—JT03184 Tee Fitting with 0.020 in. Orifice CapB—JT03183 FittingC—JT03195 Tee Fitting

1. Connect expansion valve to air conditioning gauge setusing fittings (A—C).

2. Connect yellow hose to an air supply.

3. Close low-side valve and open high-side valve.

4. Adjust pressure on high-side valve to 520 kPa (5.2 bar)(75 psi) using a pressure regulator or by adjustinghigh-side valve.

5. Holding sensing bulb in hand until pressure on low-sidegauge stops increasing. Pressure must be 280—380kPa (2.8—3.8 bar) (40—55 psi).

6. Put sensing bulb in a container of ice water untilpressure on low-side gauge stops decreasing.Pressure must be 140—170 kPa (1.4—1.7 bar) (20—25 psi).



PN=747

Tests

903125,SS16 –19–03MAY93–3/3

T84

072

–UN

–08N

OV

88

7. If pressures are not correct, turn adjusting screwclockwise to decrease pressure or counterclockwise toincrease pressure. One turn will change pressureapproximately 20 kPa (0.2 bar) (3 psi).

8. If pressure cannot be adjusted to specifications, installa new valve.

90312512


PN=748

Tests

90312513

TX,9031,RP609 –19–16SEP92–1/1

Low Refrigerant Pressure Switch Test

T88

001

–UN

–08N

OV

88

SPECIFICATIONS

Switch Closing Pressure 276 ± 20 kPa (2.76 ± 0.2 bar) (40± 3 psi)

Switch Opening Pressure 220 ± 20 kPa (2.2 ± 0.2 bar) (32± 3 psi)


Volt-Ohm-Amp Meter

1. Turn key switch ON but do not start engine. Turnblower switch ON. Push air conditioner switch ON.

2. Disconnect and connect low pressure switchconnector. Compressor clutch must engage anddisengage (click).

NOTE: Low pressure switch fitting has a Schrader valveinstalled under it to prevent discharging the airconditioning system when switch is removed.

3. Remove low pressure switch. Reconnect low pressureswitch connector to harness connector. Compressorclutch must not engage.

4. The actual pressure setting of switch can be checkedby connecting it to a pressure source such as aregulated air supply or hydraulic hand pump.

5. Switch must not have continuity between terminals Aand C until pressure increases to switch closingpressure specification.

SpecificationSwitch—Closing Pressure 276 ± 20 kPa (2.76 ± 0.2 bar) (40

± 3 psi)....................

Slowly release pressure. Switch must have continuitybetween terminals A and C until pressure decreases toswitch opening pressure specification.

SpecificationSwitch—Opening Pressure 220 ± 20 kPa (2.2 ± 0.2 bar) (32

± 3 psi)....................


PN=749

Tests

90312514

TX,9031,RP598 –19–16SEP92–1/1

High Refrigerant Pressure Switch Test

T88

002

–UN

–08N

OV

88

SPECIFICATIONS

Switch Closing Pressure 1390 ± 100 kPa (13.9 ±1 bar)(220 ± 15 psi)

Switch Opening Pressure 2410 ± 100 kPa (24.1 ± 1 bar)(350 ± 15 psi)



Volt-Ohm-Amp Meter

NOTE: High pressure switch fitting has a valve installedin it to prevent discharging the air conditioningsystem when switch is removed.

1. Remove high pressure switch.

2. Connect a portable pressure source, such as ahydraulic hand pump, to high pressure switch.

3. Switch must have continuity between terminals A andC until pressure increases to switch closing pressurespecification.

4. Slowly release pressure. Switch must not havecontinuity until pressure decreases to switch closingpressure specification.

SpecificationSwitch—Closing Pressure 1390 ± 100 kPa (13.9 ±1 bar)

(220 ± 15 psi)..........................

Opening Pressure 2410 ± 100 kPa (24.1 ± 1 bar)(350 ± 15 psi)

.....................................

5. The switch can also be checked when installed in airconditioning system, however, pressure is slow toincrease to test specification.

Connect an air conditioning gauge set to service fittings atcompressor. Cover condenser with paper or plastic to stopair flow. Operate air conditioner on maximum cooling.Note high-side pressure when high pressure switch opensand then closes.


PN=750

Tests

TX,9031,RP599 –19–16SEP92–1/1

Leak Testing

1. Inspect all lines, fittings, and components for oily ordusty spots. When refrigerant leaks from thesystem, a small amount of oil is carried out with it.

2. A soap and water solution can be sprayed on thecomponents in the system to form bubbles at thesource of the leak.

3. If a leak detector is used, move the leak detectorprobe under the hoses and around the connections

at a rate of 25 mm (1 in.) per second. RefrigerantR-12 is heavier than air so it will normally be underthe leak.

4. Some Freon manufacturers add dye to Freon to aidin leak detection.

90312515

TX,9031,RP600 –19–16SEP92–1/1

Refrigerant Hoses And Tubing Inspection

When a component is disconnected from the system,special care should be given to inspecting hoses andtubing for moisture, grease, dirt, rust, or other foreignmaterial. If such contamination is present in hoses,tubing, or fittings and cannot be removed by cleaning,then replace parts.

Fittings that have grease or dirt on them should bewiped clean with a cloth dampened with alcohol.Chlorinated solvents (such as trichloroethylene) arecontaminants, and must not be used for cleaning.

To assist in making leak-proof joints, use a smallamount of clean 525 viscosity refrigerant oil on all

hose and tube connections. Dip O-rings in 525 oilbefore assembling.

IMPORTANT: Hose used for air conditioningsystems contains special barriers inits walls to prevent migration ofrefrigerant gas.

DO NOT use hydraulic hoses asreplacement hoses in the airconditioning system. Use ONLYcertified hose meeting SAE J51brequirements.


PN=751

Tests

90312516


PN=752

IndexPage Page

A Cylinder . . . . . . . . . . . . . . . . . . . . . . .9025-05-163Arm cylinder

Restrictor adjustment . . . . . . . . . . . . . .9025-20-12AccessoryElectrical . . . . . . . . . . . . . . . . . . . . . . . .9015-20-16 Arm cylinder restrictor. . . . . . . . . . . . . . . .9025-05-64

Arm regenerative valveOperational checkout . . . . . . . . . . . . . .9005-10-37Actuator Operation (SN 546277—556935) . . . . .9025-05-92

Operation (SN 556936—) . . . . . . . . . . .9025-05-99Engine speed control fast idle . . . . . . . .9025-05-19Engine speed control, operation . . . . . .9025-05-18Engine speed manual override . . . . . . .9025-05-20

Adjustment BEngine speed sensor . . . . . .9010-20-7, 9015-20-7Travel alarm volume . . . . . . . . . . . . . . .9015-20-18

BatteryAir conditioning

Booster . . . . . . . . . . . . . . . . . . . . . . . . .9015-20-14Charge the system . . . . . . . . . . . . . . . . .9031-20-6

Electrolyte level. . . . . . . . . . . . . . . . . . .9015-20-11Circuit operation . . . . . . . . . . . . . . . . . . .9031-05-4

Malfunctions . . . . . . . . . . . . . . . . . . . . .9015-20-10Component location (SN —541550) . . . .9031-15-3

Operation . . . . . . . . . . . . . . . . . . . . . . . .9015-20-8Compressor belt tension . . . . . . . . . . . . .9031-20-8

Specification . . . . . . . . . . . . 9015-20-9, 9015-20-15Compressor oil . . . . . . . . . . . . . . . . . . . .9031-20-2

Terminal . . . . . . . . . . . . . . . . . . . . . . . .9015-20-11Compressor relief valve operation. . . . .9031-05-11

Testing . . . . . . . . . . . . . . . . . . . . . . . . .9015-20-13Diagnostic information (SN —541550) . .9031-15-1

Bearing, swing operation . . . . . . . . . . . . .9020-05-44Electrical circuit checks . . . . . . . . . . . . . .9031-10-8

BoomEvacuate the system. . . . . . . . . . . . . . . .9031-20-5

Anti-drift valve . . . . . . . . . . . . . . . . . . .9025-05-104Expansion valve . . . . . . . . . . . . . . . . . .9031-25-10

Cylinder . . . . . . . . . . . . . . . . . . . . . . .9025-05-163Expansion valve operation . . . . . . . . . .9031-05-10

Lower with engine stopped . . . . . . . . . . .9025-20-4Expansion valve, bench test . . . . . . . . .9031-25-11

Raise with engine stopped . . . . . . . . . . .9025-20-6Fan operation . . . . . . . . . . . . . . . . . . . . .9031-05-6

Boom cylinderGauge set installation . . . . . . . . . . . . . . .9031-20-3

Restrictor adjustment (SN 556936—High pressure switch test . . . . . . . . . . .9031-25-14

). . . . . . . . . . . . . . . . . . . . . . . . . . . . .9025-20-14Hoses and tubing inspection . . . . . . . . .9031-25-15

Boom cylinder restrictor (SN 556936—Leak testing . . . . . . . . . . . . . . . . . . . . .9031-25-15

) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9025-05-66Low pressure switch test. . . . . . . . . . . .9031-25-13

Boom regenerative valveOperational check . . . . . . . . . . . . . . . . . .9031-10-1

Operation (SN 545157—556935) . . . . .9025-05-86Receiver/dryer operation . . . . . . . . . . . . .9031-05-8

Boom, swing, and arm control valveRefrigerant (R-12) caution. . .9031-20-1, 9031-25-1

Component location (SN 556936—) . . .9025-05-54Refrigerant recovery . . . . . . . . . . . . . . . .9031-20-4

Schematic (SN 556936—). . . . . . . . . . .9025-05-56Refrigerant, adding . . . . . . . . . . . . . . . . .9031-20-7

Brake pressure reducing valveSystem operation . . . . . . . . . . . . . . . . . .9031-05-2 IndxOperation . . . . . . . . . . . . . . . . . . . . . . .9020-05-36System testing . . . . . . . . . . . . . . . . . . . .9031-25-2 1Bucket

Air filterCylinder . . . . . . . . . . . . . . . . . . . . . . .9025-05-163

Restriction indicator switch test . . . . . . . .9010-25-3Air intake system

Operational checkout . . . . . . . . . . . . . . .9010-10-6Air intake system leakage C

Test . . . . . . . . . . . . . . . . . . . . . . . . . . . .9010-25-4Alternator Capacities . . . . . . . . . . . . . . . . . . . . . . . . .9000-02-4

Carrier rollerTest (Bosch) . . . . . . . . . . . . . . . . . . . . .9015-20-16Test (Delco) . . . . . . . . . . . . . . . . . . . . .9015-20-15 Operation . . . . . . . . . . . . . . . . . . . . . . .9020-05-41

Carrier roller oil specification . . . . . . . . . . .9000-04-4Anti-drift valveOperation . . . . . . . . . . . . . . . . . . . . . .9025-05-104 Case drain flow

Swing motor . . . . . . . . . . . . . . . . . . . . .9025-25-64Anticavitation and circuit relief valveOperation . . . . . . . . . . . . . . . . . . . . . . .9025-05-80 Circuit

Pilot, operation . . . . . . . . . . . . . . . . . . .9025-05-13ArmAnti-drift valve . . . . . . . . . . . . . . . . . . .9025-05-104 Propel operation . . . . . . . . . . . . . . . . . . .9020-05-8

TM1508 (12JUL05) Index-1 690E LC Excavator Operation and Tests080805

PN=1

Index

Page Page

Circuit relief and anticavitation valve Cooling system checks. . . . . . . . . . . . . . . .9010-10-2Counterbalance valveOperation . . . . . . . . . . . . . . . . . . . . . . .9025-05-80

Circuit relief valve Braking operation . . . . . . . . . . . . . . . . .9020-05-29Neutral operation . . . . . . . . . . . . . . . . .9020-05-27Auxiliary function. . . . . . . . . . . . . . . . . .9025-25-70

Dig function (SN —556935) . . . . . . . . .9025-25-16 Propel operation . . . . . . . . . . . . . . . . . .9020-05-28Crossover relief valveDig function (SN 556936—) . . . . . . . . .9025-25-19

Combined function shuttle valve Propel motor . . . . . . . . . . . . . . . . . . . . . .9020-25-7Propel motor, operation. . . . . . . . . . . . .9020-05-34Operation (SN —556935) . . . . . . . . . . .9020-05-15

Operation (SN 556936—) . . . . . . . . . . .9020-05-16 Swing motor . . . . . . . . . . . . . . . . . . . . .9025-25-35Cycle timeComponent location

Air conditioning (SN —541550) . . . . . . . .9031-15-3 Operational checkout . . . . . . . . . . . . . . .9025-10-9Propel speed. . . . . . . . . . . . . . . . . . . . . .9020-25-4Main hydraulic circuit (SN —

556935) . . . . . . . . . . . . . . . . . . . . . . .9025-15-10 Cycle timesLong front . . . . . . . . . . . . . . . . . . . . . . .9025-25-75Main hydraulic circuit (SN 556936—

). . . . . . . . . . . . . . . . . . . . . . . . . . . . .9025-15-13 Standard front . . . . . . . . . . . . . . . . . . . .9025-25-72CylinderPilot circuit (SN —556935) . . . . . . . . . . .9025-15-9

Pilot circuit (SN 556936—) . . . . . . . . . .9025-15-12 Arm, boom and bucket . . . . . . . . . . . .9025-05-163Cylinder driftPropel . . . . . . . . . . . . . . . . . . . . . . . . . .9020-15-13

Compressor Test, boom, arm and bucket . . . . . . . . .9025-25-60Belt tension. . . . . . . . . . . . . . . . . . . . . . .9031-20-8Oil, air conditioning . . . . . . . . . . . . . . . . .9031-20-2

Control lever pattern conversion . . . . . . . .9025-15-22 DControl manifold

Pressure, operation (SN —556935) . .9025-05-116Diagnose malfunctions

Control systemPropel system . . . . . . . . . . . . . . . . . . . . .9020-15-1

Operation . . . . . . . . . . . . . . . . . . . . . . .9025-05-12Diesel engine oil . . . . . . . . . . . . . . . . . . . . .9000-04-2

Control valveDiesel fuel . . . . . . . . . . . . . . . . . . . . . . . . .9000-04-1

Boom, arm and bucket—combined . . . .9025-05-76Diesel fuel conditioner

Boom, arm and bucket—fullLow sulfur . . . . . . . . . . . . . . . . . . . . . . . .9000-04-1

actuation . . . . . . . . . . . . . . . . . . . . . .9025-05-74Dig function circuit relief valve

Boom, arm and bucket—neutral . . . . . .9025-05-70Test and adjustment (SN —556935) . . .9025-25-16

Boom, arm and bucket—start toTest and adjustment (SN 556936—) . . .9025-25-19

move . . . . . . . . . . . . . . . . . . . . . . . . .9025-05-72Dig pilot check valve

Manifold operation (SN —556935) . . . .9025-05-60Operation . . . . . . . . . . . . . . . . . . . . . . .9025-05-28

Manifold operation (SN 556936—) . . . .9025-05-62Digital Thermometer Installation . . . . . . . . 9020-25-1,

Operational checkout . . . . . . . . . . . . . . .9025-10-89025-20-1, 9025-25-1

Propel, operation. . . . . . . . . . . . . . . . . .9020-05-18Drain circuit

Return anticavitation check valve . . . . .9025-25-44Operation . . . . . . . . . . . . . . . . . . . . . .9025-05-159

Sections operation . . . . . . . . . . . . . . . .9025-05-68

Indx2

DriftSpool stop screw adj., long front . . . . . .9025-20-20

Test, boom, arm and bucket cylinder . .9025-25-60Spool stop screw adjustment . . . . . . . .9025-20-16

Dual solenoid blockSwing . . . . . . . . . . . . . . . . . . . . . . . . . .9025-05-78

Operation . . . . . . . . . . . . . . . . . . . . . . .9025-05-30Control valve and manifold

Component location (SN —556935) . . .9025-05-50Schematic (SN —556935). . . . . . . . . . .9025-05-52

Control valve manifold EOperation (SN 556936—) . . . . . . . . . .9025-05-118

Controller ElectricalAlternator test—Bosch . . . . . . . . . . . . .9015-20-16System, operation . . . . . . . . . . . . . . . . . .9025-05-3

Conversion Alternator test—Delco . . . . . . . . . . . . . .9015-20-15Battery specification . . . . . . . . . . . . . . . .9015-20-9Control lever pattern . . . . . . . . . . . . . . .9025-15-22

Cooling system Cab harness wiring diagram . . . . . . . . .9015-10-11Circuit malfunctions. . . . . . . . . . . . . . . . .9015-05-2Operational checkout . . . . . . . . . . . . . . .9005-10-4


PN=2

Index

Page Page

Component identification. . . . . . . . . . . . .9015-10-1 EngineBoost starting . . . . . . . . . . . . . . . . . . . .9015-20-14Component location diagram. . . . . . . . . .9015-10-7

Engine harness wiring diagram . . . . . . .9015-10-13 Diagnose malfunctions . . . . . . . . . . . . . .9010-15-2General description . . . . . . . . . . . . . . . . .9010-05-2Fuse specifications . . . . . . . . . . . . . . . . .9015-10-8

Grounded circuit . . . . . . . . . . . . . . . . . . .9015-05-6 Sectional view. . . . . . . . . . . . . . . . . . . . .9010-05-3Speed check. . . . . . . . . . . . . . . . . . . . . .9010-20-2High resistance circuit . . . . . . . . . . . . . . .9015-05-3

Inspection . . . . . . . . . . . . . . . . . . . . . . . .9015-05-1 Speed control system operation . . . . . . .9010-05-6Engine oilMonitor and switch panel . . . . . . . . . . . .9015-20-1

Monitor panel . . . . . . . . . . . . . . . . . . . . .9015-20-2 Diesel . . . . . . . . . . . . . . . . . . . . . . . . . . .9000-04-2Engine speed and performanceMonitor specifications . . . . . . . . . . . . . .9015-15-38

Open circuit . . . . . . . . . . . . . . . . . . . . . .9015-05-4 Operational checkout . . . . . . . . . . . . . .9010-10-12Engine speed control actuatorSchematic symbols . . . . . . . . . . . . . . . .9015-05-14

Seven step test procedure . . . . . . . . . .9015-05-11 Fast idle operation . . . . . . . . . . . . . . . .9025-05-19Manual override operation. . . . . . . . . . .9025-05-20Shorted circuit. . . . . . . . . . . . . . . . . . . . .9015-05-8

Switch panel 2 . . . . . . . . . . . . . . . . . . . .9015-20-3 Slow idle operation . . . . . . . . . . . . . . . .9025-05-18Expansion valveSwitch specifications . . . . . . . . . . . . . . .9015-15-38

System functional schematic . . . . . . . . .9015-10-14 Operating test . . . . . . . . . . . . . . . . . . . .9031-25-10Systems controller connector . . . . . . . . .9015-20-4Tab retainer connector . . . . . . . . . . . . . .9015-20-5

FTest equipment . . . . . . . . . . . . . . . . . . . .9015-05-9Test procedure . . . . . . . . . 9015-05-10, 9015-05-11

Fan driveVehicle harness wiring diagram. . . . . . .9015-10-10Operation (SN —559602) . . . . . . . . . . . .9010-05-4Wiring and schematic diagram legend. . .9015-10-3Operation (SN 559603—) . . . . . . . . . . . .9010-05-5Wiring diagram information . . . . . . . . . .9015-05-12

FilterWiring diagram, reading . . . . . . . . . . . .9015-05-13Inspection procedure, hydraulic oil . . . . .9025-25-5Electrical circuitPilot . . . . . . . . . . . . . . . . . . . . . . . . . . .9025-05-17Auto idle . . . . . . . . . . . . . . . . . . . . . . . .9015-15-50Return. . . . . . . . . . . . . . . . . . . . . . . . .9025-05-162Charging . . . . . . . . . . . . . . . . . . . . . . . . .9015-15-7

Front idlerHorn, dome light, cigar lighter . . . . . . . .9015-15-34Measure wear . . . . . . . . . . . . . . . . . . . . .9020-15-9Light . . . . . . . . . . . . . . . . . . . . . . . . . . .9015-15-30Oil specification. . . . . . . . . . . . . . . . . . . .9000-04-4Monitor . . . . . . . . . . . . . . . . . . . . . . . . .9015-15-38Operation . . . . . . . . . . . . . . . . . . . . . . .9020-05-40Power . . . . . . . . . . . . . . . . . . . . . . . . . . .9015-15-2

FuelStart aid and propel alarm. . . . . . . . . . .9015-15-88Diesel . . . . . . . . . . . . . . . . . . . . . . . . . . .9000-04-1Starting . . . . . . . . . . . . . . . . . . . . . . . . .9015-15-18Line leakage test. . . . . . . . . . . . . . . . . . .9010-25-2Switch panel 1 . . . . . . . . . . . . . . . . . . .9015-15-80

Fuel systemSwitch panel 2 . . . . . . . . . . . . . . . . . . .9015-15-84Operational checkout . . . . . . . . . . . . . .9010-10-10System controller . . . . . . . . . . . . . . . . .9015-15-59 Indx

Fuse 3Windshield wiper/washer. . . . . . . . . . . .9015-15-25Color codes . . . . . . . . . . . . . . . . . . . . . .9015-10-9Electrical diagnostic proceduresSpecification . . . . . . . . . . . . . . . . . . . . . .9015-10-8Auto idle circuit . . . . . . . . . . . . . . . . . . .9015-15-52

Charging circuit . . . . . . . . . . . . . . . . . . .9015-15-12Horn, dome light, cigarette lighter and heater

Gcircuits . . . . . . . . . . . . . . . . . . . . . . . .9015-15-36Light circuit . . . . . . . . . . . . . . . . . . . . . .9015-15-32 GearboxMonitor circuit . . . . . . . . . . . . . . . . . . . .9015-15-42 Propel, operation. . . . . . . . . . . . . . . . . .9020-05-38Power circuit . . . . . . . . . . . . . . . . . . . . . .9015-15-4 GreasePump and valve controller circuit . . . . .9015-15-61 Specification . . . . . . . . . . . . . . . . . . . . . .9000-04-5Start aid and propel alarm circuit . . . . .9015-15-90Starting circuit . . . . . . . . . . . . . . . . . . . .9015-15-22Switch panel 1 circuit . . . . . . . . . . . . . .9015-15-82 HSwitch panel 2 circuit . . . . . . . . . . . . . .9015-15-86Windshield wiper circuit. . . . . . . . . . . . .9015-15-28 Heater

Operation . . . . . . . . . . . . . . . . . . . . . . . .9031-05-1Electronic tachometer installation . . . . . . . .9010-20-1


PN=3

Index

Page Page

Hydraulic Low sulfur diesel fuel conditioner . . . . . . . .9000-04-1Lower boom with engine stopped . . . . . . . .9025-20-4Fittings, 30° cone seat . . . . . . . . . . . . . .9000-03-7

Fittings, 37° flare. . . . . . . . . . . . . . . . . . .9000-03-7 LubricantMixing . . . . . . . . . . . . . . . . . . . . . . . . . . .9000-04-7Oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9000-04-3

Hydraulic control valve Storage . . . . . . . . . . . . . . . . . . . . . . . . . .9000-04-6Lubrication systemReturn anticavitation check valve . . . . .9025-25-44

Spool stop screw adj., long front . . . . . .9025-20-20 Operational checkout . . . . . . . . . . . . . . .9010-10-8Spool stop screw adjustment . . . . . . . .9025-20-16

Hydraulic fittingFlared connections . . . . . . . . . . . . . . . . .9000-03-8

MHydraulic oil cleanup procedureUsing clean-up filter . . . . . . . . . . . . . . . .9025-25-7Using portable filter caddy. . . . . . . . . . . .9025-25-6 Main hydraulic circuit

Component location (SN —556935) . . .9025-15-10Hydraulic pumpCase drain flow test . . . . . . . . . . . . . . .9025-25-57 Component location (SN 556936—) . . .9025-15-13

Main hydraulic schematic (SN —Displacement solenoid valve test . . . . .9025-25-22Start-up procedure . . . . . . . . . . . . . . . . .9025-25-3 556935) . . . . . . . . . . . . . . . . . . . . . . . .9025-15-15

Main hydraulic schematic (SN 556936—Test using cycle time method . . . . . . . .9025-25-56Test using flow meter method . . . . . . . .9025-25-51 ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9025-15-18

Main pumpHydraulic systemComponents (SN —556935) . . . . . . . . . .9025-05-1 Operation (SN —559602) . . . . . . . . . .9025-05-128

Operation (SN 559603—) . . . . . . . . . .9025-05-130Components (SN 556936—) . . . . . . . . . .9025-05-2Diagnostic malfunctions . . . . . . . . . . . . .9025-15-1 Make-up valve

Operation . . . . . . . . . . . . . . . . . . . . . . .9025-05-82Operation (SN —556935) . . . . . . . . . . . .9025-05-8Operation (SN 556936—) . . . . . . . . . . .9025-05-10 Malfunctions

Engine . . . . . . . . . . . . . . . . . . . . . . . . . .9010-15-2Operational checkout . . . . . 9005-10-27, 9025-10-1Warm-up procedure . . . . . . 9020-25-2, 9025-20-2, Manifold

Control valve operation (SN 556936—9025-25-2Hydraulics ). . . . . . . . . . . . . . . . . . . . . . . . . . . .9025-05-118

Operation (SN —556935) . . . . . . . . . . .9025-05-60Circuit symbols . . . . . . . . . . . . . . . . . . . .9025-15-7Operation (SN 556936—) . . . . . . . . . . .9025-05-62Pressure control operation (SN —

556935) . . . . . . . . . . . . . . . . . . . . . .9025-05-116I Manifold and control valve

Component location (SN —556935) . . .9025-05-50Idler, front. . . . . . . . . . . . . . . . . . . . . . . . .9020-05-40 Schematic (SN —556935). . . . . . . . . . .9025-05-52

Measure wear . . . . . . . . . . . . . . . . . . . . .9020-15-9 Manifold returnOperation (SN 556936—) . . . . . . . . . . .9025-05-84

Manual bypass pressure reducing valve

Indx4

Test and adjustment . . . . . . . . . . . . . . .9025-25-33JManual override valve

Operational checkout . . . . . . . . . . . . . . .9025-10-9Jump starting . . . . . . . . . . . . . . . . . . . . . .9015-20-14Mixing lubricants. . . . . . . . . . . . . . . . . . . . .9000-04-7Monitor

Panel . . . . . . . . . . . . . . . . . . . . . . . . . . .9015-20-2L Monitor and switch

Panel . . . . . . . . . . . . . . . . . . . . . . . . . . .9015-20-1MotorLeakage

Air intake system, test. . . . . . . . . . . . . . .9010-25-4 Propel crossover relief valve test . . . . . .9020-25-7Propel, case drain flow test . . . . . . . . . .9020-25-12Load sense system relief valve

Test and adjustment . . . . . . . . . . . . . . .9025-25-12 Propel, operation. . . . . . . . . . . . . . . . . .9020-05-22Swing, case drain flow . . . . . . . . . . . . .9025-25-64Load sense valve differential pressure

Test and adjustment . . . . . . . . . . . . . . .9025-25-25 Swing, operation . . . . . . . . . . . . . . . . . .9025-05-34


PN=4

Index

Page Page

O Pilot controller lineComponent location—John Deere

pattern. . . . . . . . . . . . . . . . . . . . . . . .9025-15-24O-ring boss fittings . . . . . . . . . . . . . . . . . . .9000-03-4Component location—standardOil

pattern. . . . . . . . . . . . . . . . . . . . . . . .9025-15-26Specification carrier roller . . . . . . . . . . . .9000-04-4Pilot filterSpecification front idler . . . . . . . . . . . . . .9000-04-4

Operation . . . . . . . . . . . . . . . . . . . . . . .9025-05-17Specification hydraulic. . . . . . . . . . . . . . .9000-04-3Pilot pressure regulating valveSpecification propel gearbox . . . . . . . . . .9000-04-4

Operation (SN —556935) . . . . . . . . . . .9025-05-21Specification track roller . . . . . . . . . . . . .9000-04-4Operation (SN 556936—) . . . . . . . . . . .9025-05-22Oil cooler flow and pressure dropTest and adjustment . . . . . . . . . . . . . . .9025-25-10Test . . . . . . . . . . . . . . . . . . . . . . . . . . .9025-25-47

Pilot pump . . . . . . . . . . . . . . . . . . . . . . . .9025-05-16Oil filterFlow test . . . . . . . . . . . . . . . . . . . . . . . .9025-25-48Inspection procedure, hydraulic. . . . . . . .9025-25-5

Pilot shut-off valveOil filters . . . . . . . . . . . . . . . . . . . . . . . . . . .9000-04-5Linkage adjustment . . . . . . . . . . . . . . . .9025-20-11Operational checkOperation . . . . . . . . . . . . . . . . . . . . . . .9025-05-24Air conditioning . . . . . . . . . . . . . . . . . . . .9031-10-1

Power boost solenoidOperational checkoutActuated operation (SN —556935) . . .9025-05-120Accessory . . . . . . . . . . . . . . . . . . . . . . .9005-10-37Operation (SN 556936—) . . . . . . . . . .9025-05-122Air intake system . . . . . . . . . . . . . . . . . .9010-10-6

Power boost solenoid valveControl valve. . . . . . . . . . . . . . . . . . . . . .9025-10-8Test . . . . . . . . . . . . . . . . . . . . . . . . . . .9025-25-14Cooling system . . . . . . . . . . . . . . . . . . . .9005-10-4

Power trainCycle time. . . . . . . . . . . . . . . . . . . . . . . .9025-10-9Components (SN —556935) . . . . . . . . . .9020-05-1Engine lubrication system . . . . . . . . . . . .9010-10-8Components (SN 556936—) . . . . . . . . . .9020-05-2Engine speed and performance . . . . . .9010-10-12

Power train operational checks. . . . . . . . . .9020-10-1Fuel system . . . . . . . . . . . . . . . . . . . . .9010-10-10Pressure reducing valveHydraulic system. . . . . . . . . 9005-10-27, 9025-10-1

Propel brake release, test . . . . . . . . . . .9020-25-10Manual override valve. . . . . . . . . . . . . . .9025-10-9ProcedureOperator station (engine OFF) . . . . . . . .9005-10-9

Hyd oil cleanup using filter caddy . . . . . .9025-25-6Operators station (engine ON) . . . . . . .9005-10-13Hyd oil using clean-up filter . . . . . . . . . . .9025-25-7Power train . . . . . . . . . . . . . . . . . . . . . . .9020-10-1

PropelPropel system . . . . . . . . . . . . . . . . . . . . .9020-10-1Component location . . . . . . . . . . . . . . .9020-15-13Record sheet . . . . . . . . . . . . . . . . . . . . .9005-10-1Gearbox oil specification . . . . . . . . . . . . .9000-04-4Seat, doors, windows and latches. . . . .9005-10-41Pilot circuit operation (SN —556935) . . .9020-05-4Swing brake . . . . . . . . . . . . . . . . . . . . .9025-10-13

Propel brakeUndercarriage . . . . . . . . . . .9005-10-23, 9020-10-5Operation . . . . . . . . . . . . . . . . . . . . . . .9020-05-36Operator station (engine OFF)

Propel brake pressure reducing valve IndxOperational checkout . . . . . . . . . . . . . . .9005-10-95Test and Adjustment . . . . . . . . . . . . . . .9020-25-10Operators station (engine ON)

Propel circuit . . . . . . . . . . . . . . . . . . . . . . .9020-05-8Operational checkout . . . . . . . . . . . . . .9005-10-13Propel control valve

Spool stop screw adjustment . . . . . . . . .9020-20-3Propel motor

Case drain flow test . . . . . . . . . . . . . . .9020-25-12P Crossover relief valve test. . . . . . . . . . . .9020-25-7

Operation . . . . . . . . . . . . . . . . . . . . . . .9020-05-22Pilot circuit Start-up procedure . . . . . . . . . . . . . . . . .9020-25-3

Component location (SN —556935) . . . .9025-15-9 Propel pilot check valveComponent location (SN 556936—) . . .9025-15-12 Operation . . . . . . . . . . . . . . . . . . . . . . .9020-05-12Operation . . . . . . . . . . . . . . . . . . . . . . .9025-05-13 Propel pilot circuit

Pilot controller Operation (SN —556935) . . . . . . . . . . . .9020-05-4Full stroke operation . . . . . . . . . . . . . . .9025-05-27 Operation (SN 556936—) . . . . . . . . . . . .9020-05-6Metering operation . . . . . . . . . . . . . . . .9025-05-26 Propel pilot controller

Neutral operation . . . . . . . . . . . . . . . . .9020-05-10Neutral operation . . . . . . . . . . . . . . . . .9025-05-25


PN=5

Index

Page Page

RestrictorPropel speed change solenoid valveArm cylinder, operation . . . . . . . . . . . . .9025-05-64Operation . . . . . . . . . . . . . . . . . . . . . . .9020-05-30Boom cylinder, operation (SN 556936—Test . . . . . . . . . . . . . . . . . . . . . . . . . . . .9020-25-5

). . . . . . . . . . . . . . . . . . . . . . . . . . . . .9025-05-66Propel speed change valveRestrictor, arm cylinderOperation . . . . . . . . . . . . . . . . . . . . . . .9020-05-32

Adjustment . . . . . . . . . . . . . . . . . . . . . .9025-20-12Propel speed cycle time . . . . . . . . . . . . . . .9020-25-4Restrictor, boom cylinderPropel system operational checkout . . . . . .9020-10-1

Adjustment (SN 556936—) . . . . . . . . . .9025-20-14PumpReturn circuitHigh pressure control . . . . . . . . . . . . .9025-05-151

Operation . . . . . . . . . . . . . . . . . . . . . .9025-05-155Hydraulic, case drain flow test . . . . . . .9025-25-57Return manifoldLow pressure control. . . . . . . . . . . . . .9025-05-147

Operation (SN 556936—) . . . . . . . . . . .9025-05-84Main, operation (SN —559602). . . . . .9025-05-128RollerMain, operation (SN 559603—). . . . . .9025-05-130

Carrier. . . . . . . . . . . . . . . . . . . . . . . . . .9020-05-41Neutral control . . . . . . . . . . . . . . . . . .9025-05-143Track . . . . . . . . . . . . . . . . . . . . . . . . . .9020-05-42Pilot, flow test . . . . . . . . . . . . . . . . . . . .9025-25-48

Roller, lower trackPump displacement solenoidMeasure wear . . . . . . . . . . . . . . . . . . . . .9020-15-8Operation (SN —559602) . . . . . . . . . .9025-05-132

Roller, upper trackOperation (SN 559603—) . . . . . . . . . .9025-05-133Measure wear . . . . . . . . . . . . . . . . . . . . .9020-15-9Pump regulator (SN —559602)

Rotary manifoldFixed displacement operation . . . . . . .9025-05-138Operation . . . . . . . . . . . . . . . . . . . . . . .9020-05-20Maximum displacement operation . . . .9025-05-138

Minimum displacement operation . . . .9025-05-134Pump regulator (SN 559603—)

Fixed displacement operation . . . . . . .9025-05-140SMaximum displacement operation . . . .9025-05-140

Minimum displacement operation . . . .9025-05-136Safety relief valvePump, hydraulic

Operation . . . . . . . . . . . . . . . . . . . . . .9025-05-126Displacement solenoid valve test . . . . .9025-25-22SchematicStart-up procedure . . . . . . . . . . . . . . . . .9025-25-3

Main hydraulic (SN —556935) . . . . . . .9025-15-15Test using cycle time method . . . . . . . .9025-25-56Main hydraulic (SN 556936—) . . . . . . .9025-15-18Test using flow meter method . . . . . . . .9025-25-51

Schematic, hydraulicPump, pilotArm anti-drift valve . . . . . . . . . . . . . . . .9025-05-59Operation . . . . . . . . . . . . . . . . . . . . . . .9025-05-16Arm regenerative valve . . . . . . . . . . . . .9025-05-59Boom anti-drift valve . . . . . . . . . . . . . . .9025-05-58Boom regenerative valve . . . . . . . . . . .9025-05-58Boom, swing, and arm control valve (SN 556936—R ). . . . . . . . . . . . . . . . . . . . . . . . . . . . .9025-05-56Control valve and manifold (SN —

Indx6

Radiator 556935) . . . . . . . . . . . . . . . . . . . . . . .9025-05-52Air flow test. . . . . . . . . . . . . . . . . . . . . . .9010-25-5 Swing and torque control valves . . . . . .9025-05-57

Raise boom with engine stopped . . . . . . . .9025-20-6 Seat, doors, windows and latchesReceiver/dryer Operational checkout . . . . . . . . . . . . . .9005-10-41

Operation . . . . . . . . . . . . . . . . . . . . . . . .9031-05-8 Shuttle valveRecord sheet Combined function (SN —556935) . . . .9020-05-15

Operational checkout . . . . . . . . . . . . . . .9005-10-1 Combined function (SN 556936—) . . . .9020-05-16Refrigerant Propel motor, operation. . . . . . . . . . . . .9020-05-34

Add, air conditioning . . . . . . . . . . . . . . . .9031-20-7 SolenoidCaution, (R-12) . . . . . . . . . . . . . . . . . . . .9031-20-1 Power boost operation (SN 556936—Recovery, air conditioning . . . . . . . . . . . .9031-20-4 ). . . . . . . . . . . . . . . . . . . . . . . . . . . .9025-05-122

Reservoir Power boost—actuated operation (SN —Hydraulic. . . . . . . . . . . . . . . . . . . . . . .9025-05-162 556935) . . . . . . . . . . . . . . . . . . . . . .9025-05-120

Propel speed change valve. . . . . . . . . .9020-05-30Pressure test. . . . . . . . . . . . . . . . . . . . .9025-25-46


PN=6

Index

Page Page

Pump displacement operation (SN — Swing control valve . . . . . . . . . . . . . . . . .9025-05-78Swing crossover relief valve559602) . . . . . . . . . . . . . . . . . . . . . .9025-05-132

Pump displacement operation (SN 559603— Operation . . . . . . . . . . . . . . . . . . . . . . .9025-05-36Relief operation. . . . . . . . . . . . . . . . . . .9025-05-38). . . . . . . . . . . . . . . . . . . . . . . . . . . .9025-05-133

Swing brake release, operation. . . . . . .9025-05-32 Swing gearboxOperation . . . . . . . . . . . . . . . . . . . . . . .9025-05-48Solenoid block

Dual, operation . . . . . . . . . . . . . . . . . . .9025-05-30 Swing motorCase drain flow. . . . . . . . . . . . . . . . . . .9025-25-64Solenoid valve

Propel speed change, test . . . . . . . . . . .9020-25-5 Crossover relief valve test. . . . . . . . . . .9025-25-35Operation . . . . . . . . . . . . . . . . . . . . . . .9025-05-34Specification

Battery . . . . . . . . . . . . . . . .9015-20-9, 9015-20-15 Start-up procedure . . . . . . . . . . . . . . . . .9025-25-4Swing stop cushion valve (546277—Carrier roller oil . . . . . . . . . . . . . . . . . . . .9000-04-4

Front idler oil. . . . . . . . . . . . . . . . . . . . . .9000-04-4 ). . . . . . . . . . . . . . . . . . . . . . . . . . . . .9025-05-41Swing stop cushion valveFuse . . . . . . . . . . . . . . . . . . . . . . . . . . . .9015-10-8

Grease . . . . . . . . . . . . . . . . . . . . . . . . . .9000-04-5 Operation (546277—) . . . . . . . . . . . . . .9025-05-41Swing torque control valveHydraulic oil . . . . . . . . . . . . . . . . . . . . . .9000-04-3

Monitor gauges . . . . . . . . . . . . . . . . . . .9015-15-38 Long front (SN —546276) . . . . . . . . . .9025-05-108Long front, test (SN —546276) . . . . . . .9025-25-38Pressure switches. . . . . . . . . . . . . . . . .9015-15-38

Propel gearbox oil . . . . . . . . . . . . . . . . . .9000-04-4 Operation (SN 546277—) . . . . . . . . . .9025-05-110Test (SN 546277—) . . . . . . . . . . . . . . .9025-25-41System controller circuit solenoids . . . .9015-15-61

Track roller oil . . . . . . . . . . . . . . . . . . . . .9000-04-4 Swing upperstructure with enginestopped. . . . . . . . . . . . . . . . . . . . . . . . . .9025-20-8Specifications

690E LC . . . . . . . . . . . . . . . . . . . . . . . . .9000-02-1 SwitchAir filter restriction test . . . . . . . . . . . . . .9010-25-3690E LC long front . . . . . . . . . . . . . . . . .9000-02-3

Speed High pressure, air condition test . . . . . .9031-25-14Low pressure, air conditioning test . . . .9031-25-13Engine . . . . . . . . . . . . . . . . . . . . . . . . . .9010-20-2

Speed control system Switch panel 2 . . . . . . . . . . . . . . . . . . . . . .9015-20-3Operation . . . . . . . . . . . . . . . . . . . . . . . .9025-05-4Engine, operation . . . . . . . . . . . . . . . . . .9010-05-6

Spool stop screw System controllerOperation . . . . . . . . . . . . . . . . . . . . . . . .9025-05-3Adjustment . . . . . . . . . . . . . . . . . . . . . .9025-20-16

Adjustment, long front . . . . . . . . . . . . . .9025-20-20 System controller circuitSpecification . . . . . . . . . . . . . . . . . . . . .9015-15-61Adjustment, propel control valve . . . . . . .9020-20-3

Start-up procedure System relief valveLoad sense, operation. . . . . . . . . . . . .9025-05-124Hydraulic pump. . . . . . . . . . . . . . . . . . . .9025-25-3

Propel motor . . . . . . . . . . . . . . . . . . . . . .9020-25-3 Test and adjustment . . . . . . . . . . . . . . .9025-25-12Swing brake and gearbox . . . . . . . . . . . .9025-25-4Swing motor . . . . . . . . . . . . . . . . . . . . . .9025-25-4 Indx

7Stop screwTPropel control valve . . . . . . . . . . . . . . . .9020-20-3

Storing lubricants . . . . . . . . . . . . . . . . . . . .9000-04-6Supply shuttle valve Tachometer installation

Electronic clamp-on. . . . . . . .9020-25-1, 9025-25-1Operation . . . . . . . . . . . . . . . . . . . . . . .9020-05-26Swing Temperature analyzer installation . . . . . . . .9025-25-1

Thermometer Installation, Digital . . . . . . . 9020-25-1,Gearbox operation . . . . . . . . . . . . . . . .9025-05-48Swing bearing 9025-20-1, 9025-25-1

TM worksheet. . . . . . . . . . . . . . . . . . . . . .9025-25-77Operation . . . . . . . . . . . . . . . . . . . . . . .9020-05-44Swing brake Torque value

Flared connections . . . . . . . . . . . . . . . . .9000-03-8Operational checkout . . . . . . . . . . . . . .9025-10-13Swing brake and gearbox Flat face O-ring seal fitting . . . . . . . . . . .9000-03-6

Inch SAE four bolt flange fitting. . . . . . . .9000-03-9Lubrication and cooling flow test . . . . . .9025-25-68Start-up procedure . . . . . . . . . . . . . . . . .9025-25-4 Metric cap screw. . . . . . . . . . . . . . . . . . .9000-03-3

Metric four bolt flange fitting . . . . . . . . .9000-03-10Swing brake release solenoidOperation . . . . . . . . . . . . . . . . . . . . . . .9025-05-32 O-Ring boss fitting . . . . . . . . . . . . . . . . .9000-03-4


PN=7

Index

Page Page

30° cone seat hydraulic fittings . . . . . . . .9000-03-7 Boom, arm and bucket—start tomove . . . . . . . . . . . . . . . . . . . . . . . . .9025-05-7237° flare hydraulic fittings . . . . . . . . . . . .9000-03-7

Track Boom, swing, and arm control valve schematic (SN556936—) . . . . . . . . . . . . . . . . . . . . .9025-05-56Adjuster operation. . . . . . . . . . . . . . . . .9020-05-39

Measure bushing wear . . . . . . . . . . . . . .9020-15-6 Boom, swing, and arm control valve (SN 556936—). . . . . . . . . . . . . . . . . . . . . . . . . . . . .9025-05-54Measure link wear. . . . . . . . . . . . . . . . . .9020-15-7

Measure pitch . . . . . . . . . . . . . . . . . . . .9020-15-10 Brake pressure reducing, operation. . . .9020-05-36Circuit relief auxiliary function . . . . . . . .9025-25-70Measure shoe grouser wear . . . . . . . . .9020-15-11

Propel gearbox operation . . . . . . . . . . .9020-05-38 Circuit relief operation . . . . . . . . . . . . . .9025-05-80Combined function shuttle (SN —Roller oil specification . . . . . . . . . . . . . . .9000-04-4

Track chain 556935) . . . . . . . . . . . . . . . . . . . . . . .9020-05-15Combined function shuttle (SN 556936—Measure bushing wear . . . . . . . . . . . . . .9020-15-6

Measure link wear. . . . . . . . . . . . . . . . . .9020-15-7 ). . . . . . . . . . . . . . . . . . . . . . . . . . . . .9020-05-16Compressor relief, operation . . . . . . . . .9031-05-11Measure pitch . . . . . . . . . . . . . . . . . . . .9020-15-10

Track roller Control valve and manifold schematic (SN —556935) . . . . . . . . . . . . . . . . . . . . . . .9025-05-52Operation . . . . . . . . . . . . . . . . . . . . . . .9020-05-42

Track roller, lower Control valve and manifold (SN —556935) . . . . . . . . . . . . . . . . . . . . . . .9025-05-50Measure wear . . . . . . . . . . . . . . . . . . . . .9020-15-8

Track roller, upper Control valve manifold operation (SN —556935) . . . . . . . . . . . . . . . . . . . . . . .9025-05-60Measure wear . . . . . . . . . . . . . . . . . . . . .9020-15-9

Track sag Control valve manifold operation (SN 556936—). . . . . . . . . . . . . . . . . . . . . . . . . . . . .9025-05-62Measure and adjust . . . . . . . . . . . . . . . .9020-20-1

Track shoe Control, sections operation . . . . . . . . . .9025-05-68Counterbalance—braking operation . . .9020-05-29Measure grouser wear . . . . . . . . . . . . .9020-15-11

Travel alarm Counterbalance—neutral. . . . . . . . . . . .9020-05-27Counterbalance—propel . . . . . . . . . . . .9020-05-28Volume adjustment . . . . . . . . . . . . . . . .9015-20-18Dig function circuit relief test (SN —

556935) . . . . . . . . . . . . . . . . . . . . . . .9025-25-16Dig function circuit relief test (SN 556936—

U ). . . . . . . . . . . . . . . . . . . . . . . . . . . . .9025-25-19Dig pilot check, operation . . . . . . . . . . .9025-05-28

Undercarriage Expansion, bench test. . . . . . . . . . . . . .9031-25-11Operational checkout . . . . . . . . . . . . . .9005-10-23 Expansion, operation . . . . . . . . . . . . . .9031-05-10

Undercarriage operational checkout . . . . . .9020-10-5 Expansion, test . . . . . . . . . . . . . . . . . . .9031-25-10Upperstructure Hyd pump displacement solenoid

Swing with engine stopped . . . . . . . . . . .9025-20-8 test . . . . . . . . . . . . . . . . . . . . . . . . . .9025-25-22Load sense differential press. test. . . . .9025-25-25Load sense system relief test . . . . . . . .9025-25-12Make-up, operation . . . . . . . . . . . . . . . .9025-05-82

Indx8

V Manual bypass pressure reducing. . . . .9025-25-33Pilot controller operation—neutral . . . . .9025-05-25Pilot controller-metering . . . . . . . . . . . .9025-05-26Valve

Anti-drift, operation . . . . . . . . . . . . . . .9025-05-104 Pilot controller—full stroke. . . . . . . . . . .9025-05-27Pilot pressure regulating (SN —Anticavitation operation . . . . . . . . . . . . .9025-05-80

Arm regenerative (SN 546277— 556935) . . . . . . . . . . . . . . . . . . . . . . .9025-05-21Pilot pressure regulating (SN 556936—556935) . . . . . . . . . . . . . . . . . . . . . . .9025-05-92

Arm regenerative (SN 556936—) . . . . .9025-05-99 ). . . . . . . . . . . . . . . . . . . . . . . . . . . . .9025-05-22Pilot pressure regulating test. . . . . . . . .9025-25-10Boom regenerative (SN 545157—

556935) . . . . . . . . . . . . . . . . . . . . . . .9025-05-86 Pilot shut-off . . . . . . . . . . . . . . . . . . . . .9025-05-24Pilot shut-off linkage adjustment . . . . . .9025-20-11Boom, arm and bucket—combined . . . .9025-05-76

Boom, arm and bucket—full Power boost solenoid test . . . . . . . . . . .9025-25-14Propel brake pressure reducing test . . .9020-25-10actuation . . . . . . . . . . . . . . . . . . . . . .9025-05-74

Boom, arm and bucket—neutral . . . . . .9025-05-70 Propel control, operation . . . . . . . . . . . .9020-05-18


PN=8

Index

Page

Propel crossover, operation . . . . . . . . .9020-05-34Propel motor crossover relief test . . . . . .9020-25-7Propel pilot check block—forward . . . . .9020-05-12Propel pilot controller operation. . . . . . .9020-05-10Propel speed change solenoid . . . . . . .9020-05-30Propel speed change solenoid test . . . . .9020-25-5Propel speed change—operation . . . . .9020-05-32Propel valve stop screw adjustment . . . .9020-20-3Return anticavitation check valve . . . . .9025-25-44Safety relief, operation . . . . . . . . . . . .9025-05-126Schematic, arm anti-drift . . . . . . . . . . . .9025-05-59Schematic, arm regenerative. . . . . . . . .9025-05-59Schematic, boom anti-drift. . . . . . . . . . .9025-05-58Schematic, boom regenerative . . . . . . .9025-05-58Schematic, swing torque control . . . . . .9025-05-57Shuttle, operation . . . . . . . . . . . . . . . . .9020-05-34Spool stop screw, control valve. . . . . . .9025-20-16Spool stop screw, long front . . . . . . . . .9025-20-20Supply Shuttle-Operation . . . . . . . . . . .9020-05-26Swing control . . . . . . . . . . . . . . . . . . . .9025-05-78Swing crossover relief operation . . . . . .9025-05-36Swing motor crossover relief test . . . . .9025-25-35Swing stop cushion (546277—) . . . . . .9025-05-41Swing torque control, operation (SN 546277—

). . . . . . . . . . . . . . . . . . . . . . . . . . . .9025-05-110Swing torque control—long front (SN —

546276) . . . . . . . . . . . . . . . . . . . . . .9025-05-108Swing torque, test (SN —546276). . . . .9025-25-38Swing torque, test (SN 546277—). . . . .9025-25-41System relief operation . . . . . . . . . . . .9025-05-124

W

Warm-up procedureHydraulic system. . . . . . . . . 9020-25-2, 9025-20-2,

Indx9025-25-2 9Welding on machine. . . . . . . . . . . . . . . . .9015-20-17Worksheet, TM. . . . . . . . . . . . . . . . . . . . .9025-25-77


PN=9

Index

Indx10


PN=10

jonh deere 690e lc hydraulic test manual tm1508

Documents

operation sn

cushion valve sn

valve sn return manifold

boom regenerative valve

valve sn556935

anticavitation valve

makeup valve

manifoldmain pump sn