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Service Training SESV1692

Meeting Guide 692 October 1997

TECHNICAL PRESENTATION

D11R TRACK-TYPE TRACTOR

IMPLEMENT SYSTEMS



D11R TRACK-TYPE TRACTORIMPLEMENT SYSTEMS

MEETING GUIDE 692 SLIDES AND SCRIPT

AUDIENCE

Level II--Service personnel who understand the principles of machine systems operation, diagnosticequipment, and procedures for testing and adjusting.

CONTENT

This presentation discusses the operation of the implement hydraulic system for the D11R Track-type

Tractor.

OBJECTIVES

After learning the information in this presentation, the serviceman will be able to:

1. locate and identify all major components in the implement hydraulic system;

2. locate and identify all filters, drains, and test points;

3. explain the function of each component in the implement hydraulic system; and

4. trace the flow of oil through the implement hydraulic system.

REFERENCES

D11R Track-type Tractor Service Manual (9TR 1-Up) SENR1775

D11R Track-type Tractor Service Manual (8ZR 1-Up) SENR9400

PREREQUISITES

Interactive Video Course "Fundamentals of Mobile Hydraulics" (CD ROM) TECD9001STMG 546 "Graphic Fluid Power Symbols" SESV1546

SUPPLEMENTARY TRAINING MATERIAL

STMG 679 "D10R Track-type Tractor--Introduction" SESV1679

STMG 527 "D11N Track-type Tractor--Part 2: Undercarriage, Implements, and

Operator’s Station" SESV1527

Video Tape "D11R Track-type Tractor/D11R CD Carrydozer--Introduction" SEVN4173

Estimated Time: 2 Hours

Visuals: 27 (2 X 2) SlidesServiceman Handouts: 18 Line Drawings

Form: SESV1692

Date: 10/97

© 1997 Caterpillar Inc.



STMG 692 - 3 -

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TABLE OF CONTENTS

INTRODUCTION ..................................................................................................................5

IMPLEMENT HYDRAULIC SYSTEM................................................................................6

Bulldozer Tilt Circuit........................................................................................................9Bulldozer Lift Circuit......................................................................................................12

Quick-drop Valves ..........................................................................................................19

Fan Drive Hydraulic System...........................................................................................25

Ripper and Pilot Circuits.................................................................................................26

Dual Tilt Valve................................................................................................................33

CONCLUSION.....................................................................................................................40

SLIDE LIST..........................................................................................................................41

SERVICEMAN'S HANDOUTS...........................................................................................42



INSTRUCTOR NOTES

STMG 692 - 4 -

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STMG 692 - 6 -

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2

• Continuous flow at

minimum pressurewith controls in HOLD

• Two section gear-typepump

• Pilot operated controlvalves

DUAL TILT

CONTROL VALVE

QUICK-DROP

VALVES

RIPPER

CONTROL VALVE

HYDRAULIC

TANK

PILOT VALVE

AND DOZER

CONTROL VALVE

IMPLEMENT

PUMP

FAN MOTOR AND

MAKEUP VALVE

OIL COOLER AND

BYPASS VALVE

FAN

PUMPS

IMPLEMENT HYDRAULIC SYSTEM COMPONENTS

IMPLEMENT HYDRAULIC SYSTEM

The implement hydraulic system for the D11R is a continuous flow design

that permits minimum pressure in the system when the implement control

valves are not activated. The pump for operation of the bulldozer, ripper,

and oil cooling circuits is a two section gear-type pump (large and small

sections).

The system components include: the pump, pilot operated control valves,

demand control fan pumps, dozer control valve, quick-drop valves, dualtilt control valve, and a ripper control valve. The system components

control the flow of hydraulic oil to the appropriate implement cylinders.



• Hydraulic tankcomponents:

1. Oil fill tube

2. Manual air vent

3. Hydraulic oil filters4. Sight gauge

5. S•O•S tap

6. Tank drain

3

The hydraulic tank is located on the right fender just outside the operator's

compartment. The oil fill tube and cap (1) are located on the top of the

tank. Inside the fill tube is a fine mesh screen which removes large

particles of dirt or foreign material from the oil as the tank is filled. A

manual air vent (2) and the breaker relief valve (not visible) are located

near the filters. The vacuum breaker relief valve has a pressure setting of 3.5 kPa (.5 psi). Two hydraulic oil filters (3) are located inside the tank.

The oil level sight gauge (4) on the front of the tank permits an easy

check of the hydraulic system oil level. Always clean the sight gauge to

be sure the oil level is visible. Dirt and stains on the glass frequently give

the appearance of a full tank. A scheduled oil sampling (S•O•S) tap (5)

and tank drain (6) are located on the front of the tank.

NOTE: The capacity of the D11R hydraulic system is approximately

205 Liters (54 gal.).

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32

1

5

6

4



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4

• Dozer control valvecomponent locations

• Manually operated

dozer lift spool

• Pilot operated bladetilt spool

FROM SMALL PUMP

FROM LARGE PUMP

FROM PILOT VALVE

ROD END LIFT CYLINDER

HEAD END LIFT CYLINDER

ROD END

TILT CYLINDER

HEAD END

TILT CYLINDER

LIFT SPOOL

LIFT RELIEF

VALVE

TILT

SPOOL

DOZER CONTROL VALVEHOLD

The dozer control valve is located below the operator's station on the right

side of the machine. Inside the control valve are two spools. One spool is

for blade lift and lower and one spool is for blade tilt. The blade lift spool

is manually operated and the blade tilt spool is operated by pilot oil.

The manually operated dozer lift spool has four positions: RAISE,

HOLD, LOWER, and FLOAT. Only the FLOAT position has a detent.

The pilot operated blade tilt spool has three positions: TILT RIGHT,

HOLD, and TILT LEFT. None of these positions has a detent.

The tilt circuit receives oil from the small section of the pump. When the

circuit is not in use, the oil joins the large pump section oil flow to the lift

circuit. If neither circuit is in use, the dump valve opens and sends oil

flow to the tank. Both the tilt and lift circuits have load check valves and

relief valves. The lift circuit has makeup valves for both the rod and head

ends of the lift cylinders.



STMG 692 - 9 -

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5

A A

SECTION A-A

FROM SMALL PUMP

FROM LARGE PUMP

FROM PILOT VALVE

DOZER TILT SPOOLHOLD

TILT RIGHT TILT LEFT

Bulldozer Tilt Circuit

The tilt spool has three positions: TILT RIGHT, HOLD, and TILT LEFT.

The tilt spool is hydraulically operated by pilot pressure from a pilot valve

which is controlled by the blade control lever. Movement of the lever to

the right sends pilot pressure oil to the left end of the of the tilt valve

spool. The pilot pressure moves the spool to the right and sends oil from

the pump to the rod end of the tilt cylinder, and the blade tilts right. Lever

movement to the left sends pilot pressure oil to the right end of the spool.

The spool moves to the left, sends pump oil to the tilt cylinders, and theblade tilts left. When the blade control lever is released from either the

TILT RIGHT or TILT LEFT position, springs return the tilt spool to the

HOLD position.

In the HOLD position, the oil from the small section of the pump goes

around the tilt spool and joins the oil from the large section of the pump.

The oil then opens the dump valve and returns to the tank.

• Tilt circuit component

locations



STMG 692 - 10 -

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6

• Pilot oil moves tiltspool to right

• Pressure opens load

check valve

• Oil goes to tilt cylinder

to retract rod

A A

SECTION A-A

DOZER TILT SPOOLTILT RIGHT

TILT RIGHT TILT LEFT

FROM SMALL PUMP

FROM LARGE PUMP

FROM PILOT VALVE

When the dozer control lever is moved to the TILT RIGHT position, pilot

oil goes to the left end of the tilt spool. The pressure of the pilot oil

moves the tilt spool to the TILT RIGHT position. In the TILT RIGHT

position, the oil from the small section of the pump cannot go through the

control valve and the pressure of the oil increases. The increased pressure

of the oil opens the load check valve. The pump oil goes through the

open load check valve and around the tilt spool to the rod end of the tilt

cylinder. The tilt cylinder, which is connected to the upper rear of the

blade, retracts and causes the right end of the blade to move downward or

TILT RIGHT.

When the dozer control lever is released, the pilot oil at the left end of the

tilt spool is drained. The spring at the right end of the tilt spool moves the

spool to the HOLD position. In the HOLD position, the oil in the head

and rod ends of the tilt cylinder is blocked. The tilt angle of the blade will

not change until the dozer control lever is moved.



•Tilt circuit relief valve With the tilt spool in the TILT RIGHT position, flow from the small

section of the pump does not combine with flow from the large section.

Pilot oil at the left end of the tilt spool has moved the spool to the right.

Flow from the small section of the pump goes around the tilt spool and is

sent to the rod end of the tilt cylinder. Because the small section flow

cannot combine with the oil in the center chamber, the dump valve for the

dozer lift circuit does not control the tilt circuit pressure. Instead, the tilt

relief valve (at the top of the valve body) is used to limit the pressure in

the tilt circuit. When the tilt cylinder pressure increases to 24300 kPa

(3525 psi), the pilot valve for tilt relief will open and drain the spring

chamber behind the valve spool. This condition permits the valve spool

to open and limit the pressure in the tilt circuit.

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7

• Lift circuit

components

FROM LARGE PUMP

LIFT RELIEFVALVE

LIFT SPOOL

DOZER LIFT SPOOLHOLD

Bulldozer Lift Circuit

The lift spool has four positions: RAISE, HOLD, LOWER, and FLOAT.

The lift spool is manually operated by the blade control lever. Movement

of the lever to the rear sends pressure oil to the rod end of the lift

cylinders, causing the blade to RAISE. Forward movement of the dozer

control lever sends pressure oil to the head end of the lift cylinders,

causing the blade to LOWER. If the lever is pushed forward past the

LOWER position, the lever will go into the FLOAT position. The FLOAT

position is the only position with a detent. In the FLOAT position, theblade is free to move up or down according to outside forces.

In the HOLD position, oil from the large section of the pump goes to the

lift spool where it joins the oil from the tilt circuit.



STMG 692 - 13 -

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8

• HOLD position



ROD END

TILT CYLINDER

HEAD END

TILT CYLINDER

LIFT SPOOL

LIFT RELIEF

VALVE

TILT

SPOOL

SHUTTLE

VALVE

BALL

RESOLVER

FROM SMALL PUMP

FROM LARGE PUMP

FROM PILOT VALVE


When the valve spools in both the dozer control valve and the ripper

control valve are in the HOLD position, the pressure of the supply oil

(from both the small and large sections of the pump) through the dozer

control valve is maintained at approximately 700 kPa (100 psi).

The dozer lift spool is a "closed-center" spool, and the blade tilt spool is

an "open-center" spool. In this view, both spools are in the HOLD (or

center) position. Oil from the large pump section enters the valve and

starts to fill the chamber in the center of the valve body. Flow from the

small section of the pump enters the valve body, flows around the open-center tilt spool, and joins with the oil from the large section in the center

chamber. All the oil around the closed-center lift spool is blocked.

Because both spools are in the HOLD position, no oil flows to or from the

lift and tilt cylinders, and the load check valves cannot open.

.



• Dump valve The spring for the dump valve plus the pressure of the oil in the tank have

a combined force that provides a restriction to flow. When the pressure in

the center chamber increases above the spring force plus the tank oil

pressure, the dump valve will open and permit the combined flow from

the two sections of the pump to return to the tank. With both spools in the

HOLD position, the dump valve provides a constant low system pressure

which is available for instant implement response or for "feathering"

action of the controls when activated by the operator.

The shuttle valve resolves which hydraulic function (dozer raise and

lower or ripper) will provide pressure feedback to the spring chamber of

the dump valve. The shuttle valve is spring biased to the dozer lift and

lower function. The stem shifts to the right when oil pressure is directed

to the ripper valve port when the ripper function is requested by the

operator or during an engine overspeed condition. When the lift spool is

in the hold or center position, the spring chamber of the dump valve isconnected to the tank. Tank pressure is transmitted through passages in

the lift and lower spool that travel through the ball resolver valve and the

shuttle valve before filling the spring chamber of the dump valve. During

blade lift and lower functions, the cylinder load pressure signal is

transmitted to the ball resolver valve, through the shuttle valve, to the

spring chamber of the dump valve. This path is the same as when the

spool is in the HOLD position. The cylinder load pressure signal is from

the lift cylinder rod end during lift and from the cylinder head end during

lower or float. The ball resolver valve directs the higher of either the

cylinder rod or head end pressure to the shuttle valve.

Because the shuttle valve spool is moved completely to the left, pressure

oil from the center chamber cannot fill the spring chamber of the dump

valve. For this reason, only the dump valve springs plus the tank oil

pressure are regulating the pressure in the center chamber. This pressure

will remain low as long as the lift and tilt spools are in the HOLD

position, and the ripper circuits are not activated.

STMG 692 - 14 -

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• Shuttle valve



STMG 692 - 15 -

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9

• Dozer RAISE

FROM LARGE PUMP

LIFT RELIEF

VALVE

DOZER LIFT SPOOLRAISE

LIFT SPOOL

This view of the dozer control valve shows spool movement and oil flow

when the control lever is moved to the RAISE position. Movement of the

dozer lift spool to the RAISE position opens the chamber at the left center

of the spool, which is connected to the rod end of the lift cylinders. Since

the oil around the lift spool is no longer blocked, pressure oil from the

center chamber of the valve body can open the load check valve and flow

around the lift spool to the rod end of the lift cylinders.

At the same time that pressure oil is sent to the lift cylinders, oil also

flows to the ball resolver valve. The ball resolver valve operates similarlyto a check valve. With the lift spool in the RAISE position, the ball

resolver valve permits pressure oil to flow to the shuttle valve, but blocks

flow to the drain passage at the right end of the ball resolver valve.



• Dump valve converted

to pilot operated reliefvalve

During blade RAISE, the lift cylinder rod end pressure is transmitted to

the spring chamber of the dump valve through the ball resolver and the

shuttle valve. The dump valve uses the rod end cylinder pressure

combined with the spring to move the dump valve to the right until the

supply pressure is 700 kPa (100 psi) above the cylinder pressure. If the

pressure in the dump valve spring chamber reaches 22750 kPa (3300 psi)

due to cylinder load or an end stroke condition, the relief valve will open

and allow spring chamber oil to drain to the tank. When oil is allowed to

drain from the dump valve spring chamber, the dump valve moves to the

left and allows pump flow to pass around the dump valve to the tank.

This operation prevents the system pressure from exceeding 22750 kPa

(3300 psi) during blade RAISE or LOWER.

An additional condition can exist during dozer operation which is referred

to as "feathering the blade." If the operator moves the control lever a

small distance to gradually raise the blade, flow to the cylinders goesthrough the throttling slots in the lift spool. Flow through the throttling

slots can create the same effect as an orifice by restricting the flow of oil

to the lift cylinder and and to the spring chamber of the dump valve. This

restriction to flow causes a pressure difference between the oil in the

center chamber of the valve body (system pressure) and the oil in the

spring chamber of the dump valve (cylinder pressure). If the pressure

difference is greater than the spring force, the dump valve will open and

permit some of the pump flow to return to the tank.

With the lift spool in the RAISE position, the load check valve is used to

prevent reverse oil flow from the cylinders which can cause "cylinderdrift."

When the lift spool is held in the FLOAT position by the detents on the

end of the spool, the load check valve is open. The supply oil in the

center chamber goes through the open load check valve to the head end of

the lift cylinders. The center chamber is also open to the tank. The

weight of the blade is the force that moves the dozer down. The oil from

the rod end of the lift cylinders is also open to the tank when the lift spool

is in the FLOAT position. When an outside force moves the blade up, the

pressure of the oil in the rod end of the lift cylinders decreases as the rodsretract. The pressure of the oil in the rod end circuit is less than the

pressure in the head end circuit. The higher pressure in the head end

circuit opens a makeup valve to fill the rod end circuit as needed.

The dozer control lever must be moved from the FLOAT position to move

the lift spool in the dozer control valve from the FLOAT position.

STMG 692 - 16 -

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• Blade "feathering"

• Load check valve

prevents drift

• FLOAT position



STMG 692 - 17 -

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10

• Dump valve has fourfunctions:

1. Release pump flow

with levers inHOLD

2. Pressurecompensation

valve for pump




ROD END

TILT CYLINDER

HEAD ENDTILT CYLINDER

LIFT SPOOL

LIFT RELIEF

VALVE

TILT SPOOL

DUMP

VALVE

FROM SMALL PUMP

FROM LARGE PUMP

FROM PILOT VALVE

The dump valve in the dozer control valve has four different functions in

the dozer lift and ripper circuits.

When the blade lift and ripper control spools are in the HOLD position,

the pressure in the spring chamber of the dump valve is the same as tank

pressure plus 700 kPa (100 psi), which is the value of the spring. During

blade RAISE or LOWER, the pressure in the spring chamber of the dump

valve is the same as the pressure in either the head end or rod end of the

lift cylinders. This pressure is felt through the ball resolver valve and the

shuttle valve. With the cylinder pressure plus the spring force behind thedump valve, the supply pressure will be raised to a level of 700 kPa

(100 psi) above the cylinder pressure. Flow control and fine modulation

are possible because of the constant 700 kPa (100 psi) pressure behind the

dump valve.



3. Flow control

4. Relief valve formain system

operation

When the ripper control spools are activated, pilot oil is sent to the right

end of the shuttle valve and moves the shuttle valve to the left. When the

shuttle valve is moved, supply oil fills the spring chamber behind the

dump valve. The pilot valve and the dump valve now function as the

relief valve for the ripper circuit. Because oil from the drive end pump

section goes to both a passage in the dozer control valve and to the ripper

control valve, the pressure of the oil is always the same in both places.

When the lift spool is in the RAISE or LOWER position, cylinder

pressure is transmitted to the spring chamber of the dump valve through

the ball resolver valve and the shuttle valve. A pressure relief valve is

located within the dump valve spring chamber. This valve will lift off its

seat and allow the spring chamber oil to drain when the pressure in the

spring chamber reaches 22750 kPa (3300 psi). When the relief valve

opens, an imbalance exists between the pressure in the center chamber

and a combination of the dump valve spring and the pressure in the spring

chamber. A balance is achieved when the dump valve shifts to the left

allowing oil in the center chamber to drain until the pressure in the center

chamber is equal to the dump valve spring plus the spring chamber

pressure. This method of controlling maximum system pressure is called

a pilot operated relief valve.

STMG 692 - 18 -

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STMG 692 - 19 -

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11

• Quick-drop valve in

RAISE position

QUICK-DROP VALVERAISE

ROD END OIL

HEAD END OIL

Quick-drop Valves

All flow to and from the lift cylinders must go through the quick-drop

valves that are installed on top of each cylinder. The primary function of

the quick-drop valve is to allow rapid blade lower without voiding the

head end of the lift cylinders. Minimizing the amount of cylinder voiding

reduces the time delay that will occur when a rapid blade lower is

followed by an operator request for blade down pressure. The quick-drop

valve is activated when a sufficient pressure difference occurs between the

cylinder rod end oil and the oil in the spring cavity. This pressuredifference is caused by rod end oil flow through an orfice in the quick-

drop valve. The quick-drop valve is de-activated by high pressure in the

head end felt through a slot in the spool. The quick-drop valves help to

control four functions of the bulldozer: RAISE, LOWER at slow speeds,

rapid LOWER, and LOWER with down pressure.



When the dozer control lever is moved to the RAISE position, supply oil

enters the quick-drop valve through an inlet and an orifice, flows through

a sleeve, and is directed to the rod end of the lift cylinder. A small

amount of oil passes through another orifice and fills the spring chamber

behind the plunger. The pressure of this oil adds to the force of the

spring, which pushes the valve against the sleeve. This condition causes

all the oil entering the quick-drop valve to be directed to the rod end of

the lift cylinders and all the oil from the head end of the lift cylinders to

return to the tank.

STMG 692 - 20 -

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When the dozer control lever is moved to the LOWER position, supply

oil enters the quick-drop valve through a port and flows to the head end of

the lift cylinders. The oil being pushed from the rod end of the cylinders

returns through the control valve to the tank. Because of the weight of the

blade and the resistance to flow, the pressure of the rod end oil may be

higher than the head end oil. The flow of oil through the orifice is not

high enough to create a large pressure difference between the oil in the

port and the oil behind the plunger. The spring holds the valve against the

sleeve and all the oil leaving the rod end of the lift cylinder returns

through the control valve to the hydraulic tank.

STMG 692 - 22 -

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STMG 692 - 23 -

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13

• Quick-drop LOWER

QUICK-DROP VALVEQUICK-DROP

ROD END OIL

HEAD END OIL

When the dozer control lever exceeds approximately 75% of lever travel

and the cylinder head end pressure is low, the quick-drop valve is

activated and the blade drops very rapidly.

The oil flow for a quick drop is the same as slow lower except that some

of the oil leaving the rod end of the lift cylinder is directed into the head

end of the cylinder. When the flow of oil through the orifice creates

enough pressure differential between the port and the plunger spring

chamber, the valve and plunger shift to the left and permit oil leaving the

rod end to be added to the supply oil filling the head end of the liftcylinders. As mentioned earlier, during a rapid blade drop, the rod end

pressure will be higher than the head end due to the blade weight. The

resulting pressure differential and valve movement allow the rod end oil

to flow to the head end of the cylinder and minimize cylinder voiding.



STMG 692 - 24 -

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14

• LOWER with downpressure

QUICK-DROP VALVELOWER WITH DOWN PRESSURE

ROD END OIL

HEAD END OIL

When down pressure must be applied to the blade, the operator moves the

dozer control lever to the LOWER position. Pressure oil from the dozer

control valve is sent to the head end of the lift cylinders. At the same

time, oil fills the chamber at the left end of valve spool. As the head end

pressure and resistance to downward movement increase, pressure in the

chamber at the left end of the valve spool moves the plunger to the left

against the force of the spring and moves the valve spool completely to

the right. All the pressure oil from the dozer control valve is then sent to

the head end of the lift cylinders. All the rod end oil is returned through

the dozer control valve to the tank.



STMG 692 - 25 -

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15

• Fan pumps part of

hydraulic system

• Demand control fansystem equipped withtandem axial pumps

FAN

PUMPS

SOLENOID

TANK

FAN DRIVE

MOTOR

RADIATOR

OIL COOLER

OIL

COOLER

BYPASS

VALVE

FAN DRIVE

HYDRAULIC SYSTEM

TO PILOT VALVES

Fan Drive Hydraulic System

The demand control fan system on the D11R is considered part of the

implement hydraulic system because the fan pumps pull oil from the

implement hydraulic tank and send some of the oil to the pilot control

valves. Pilot oil shifts the blade tilt spool in the dozer control valve and

also shifts the spools in the ripper control valve to control ripper lift and

ripper tip.

The tractor is equipped with two hydraulic pumps for the demand controlfan system. The tandem axial (variable displacement) pumps are located

on the right rear side of the engine and are driven off the flywheel. The

system adjusts the fan speed to match the cooling system demands based

on an input signal to the engine Electronic Control Module (ECM) from

the engine coolant temperature sensor.



• Ripper control valve(arrow)

16

Ripper and Pilot Circuits

The ripper control valve (arrow) has two spools (lift and tip), two makeup

valves (one for the head end of the ripper lift cylinders and one for the

head end of the ripper tip cylinders), and a load check valve. The ripper

lift spool is operated with pilot oil pressure and has three positions:RAISE, HOLD, and LOWER. The ripper tip spool is operated by pilot

pressure oil and also has three positions: SHANK IN, HOLD, and

SHANK OUT. The valve spools have no detent positions.

Movement of the ripper control lever to the left causes the ripper to lift

and movement to the right causes the ripper to lower. When the ripper

control lever is moved forward, the ripper tip moves toward the machine

(SHANK IN). Pulling the ripper control lever toward the rear causes the

ripper tip to move away from the machine (SHANK OUT).

STMG 692 - 26 -

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STMG 692 - 27 -

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17

• Ripper RAISE

RIPPER TIPSPOOL

RIPPER LIFTSPOOL

LIFTCYLINDERS

MAKEUP VALVEFOR HEAD END

OF LIFTCYLINDERS LOAD

CHECK VALVE

RIPPERAND PILOT SYSTEMS

RAISEFROM

FAN PUMP

TO DOZERCONTROL VALVE

TO SHUTTLEVALVE

When the ripper control lever is moved to the RAISE position, pilot oil is

directed to the upper end of the lift spool and moves the spool down. The

supply oil opens the load check valve, goes around the lift spool, and

flows to the rod end of the ripper lift cylinders, causing the cylinder rods

to retract and the ripper to raise.

The oil that is forced from the head end of the ripper lift cylinders flows

through the ripper control valve, around the lift spool, and returns to the

tank.

When the ripper control lever is released, the pilot oil in the upper spring

chamber is drained. The lower spring returns the ripper lift spool to the

HOLD position. The oil is blocked and holds the ripper in position until

the ripper control lever is moved again.



STMG 692 - 28 -

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18

• Makeup valve

LIFTCYLINDERS

LOADCHECK VALVE

RIPPER TIPSPOOL

RIPPER LIFTSPOOL


OF LIFTCYLINDERS


LOWERFROM

FAN PUMP


TO SHUTTLEVALVE

The makeup valve operates when the ripper is lowered quickly. When the

lift spool is in the LOWER position, supply pressure oil is in the head end

of the ripper lift cylinders and oil is returning from the rod end of the

cylinders to the tank.

If the cylinder head end supply pressure becomes less than the tank

pressure due to the weight of the ripper, the makeup valve opens to let the

tank oil add to the supply oil. This condition prevents cavitation in the

head end of the lift cylinders and prevents delays in the operation of the

ripper.



STMG 692 - 30 -

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20

• SHANK IN

TIP

CYLINDERS RIPPER TIPSPOOL

RIPPER LIFTSPOOL


OF LIFT

CYLINDERS LOADCHECK VALVE


SHANK INFROM

FAN PUMP


When the ripper control lever is moved to the SHANK IN position, pilot

oil is directed through the ripper control valve to the upper end of the

ripper tip spool. The pressure of the pilot oil moves the ripper tip spool

down. The pump oil opens the load check valve and goes around the lift

and tip spools to the head end of the ripper tip cylinders, causing the rods

to extend and move the ripper tip toward the machine.

The oil that is pushed from the rod end of the ripper tip cylinders flows

through the ripper control valve and returns to the tank



STMG 692 - 31 -

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21

• Pilot control valves

• Dump valve acts as

ripper circuit reliefvalve

RIPPER TIPSPOOL

RIPPER LIFTSPOOL

LIFTCYLINDERS


OF LIFTCYLINDERS LOAD

CHECK VALVE


RAISEFROM

FAN PUMP


TO SHUTTLEVALVE

Three pilot valves are located below the dozer and ripper control levers to

the right of the operator. The closed-center pilot valves control the dozer

tilt, ripper lift, and ripper tip functions. No oil flows through the pilot

valves when the spools are in the HOLD position. Each valve is centered

by springs.

When the ripper circuit is activated by the operator, pilot oil from the fan

pump flows through the pilot valve to one end of the lift spool or tip

spool. At the same time, pilot oil flows to the shuttle valve in the dozer

control valve. The shuttle valve shifts to the right and allows oil to flowto the spring chamber of the dump valve which now functions as the relief

valve for the ripper circuit. When the shuttle valve is shifted, the oil from

both the small and large pumps is directed to the load check valve in the

ripper control valve.



STMG 692 - 32 -

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22

• TILT RIGHT

PILOT SYSTEM

BLADE TILT RIGHTFROM

FAN PUMP

RIGHT TILT

CYLINDER

FROM LARGE PUMP

The tilt circuit receives oil from the small section of the pump. When the

circuit is not in use, this oil combines with the oil from the large section of

the pump for the lift circuit. The tilt valve spool has three positions:

TILT RIGHT, HOLD and TILT LEFT.

The tilt valve spool is hydraulically operated by pilot oil pressure from the

pilot valve that is controlled by the dozer control lever. When the dozer

control lever is moved to the TILT RIGHT position, the linkage moves the

pilot spool down. This movement allows pilot oil to flow to the left end

of the tilt spool in the dozer control valve. Pilot pressure at the left end of the tilt spool moves the spool to the right and permits oil from the small

section of the pump to flow to the rod end of the tilt cylinder. As the rod

end pressure increases, the rod retracts and tilts the blade to the right. Oil

from the head end of the tilt cylinder is returned through the dozer control

valve to the tank.



STMG 692 - 33 -

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23

• Dual tilt valve has

three modes:

- Dual tilt

- Single tilt

- Blade pitch

• Solenoid valvecontains twopositioning coils

• Trigger switch

activates S1 coil

• Toggle switch

activates S2 coil

S1S2

DUAL TILT VALVE

TILT

CYLINDERS

PILOT OIL FROM

FAN PUMP

FROM BLADE

TILT VALVE

HOLD

TO HEAD END

TO ROD END

Dual Tilt Valve

The dual tilt attachment provides the blade tilt circuit with three different

modes of operation: DUAL TILT, SINGLE TILT, and BLADE PITCH.

The control valve is located between the radiator grill doors and the

radiator on the left side of the machine. The valve is activated by pilot oil

pressure from the solenoid valve. The dual tilt valve contains a spring

centered, hydraulically actuated spool valve and an electrically actuated

solenoid control valve.

The solenoid valve contains two coils and has three different positions.

When neither solenoid is activated, the system operates in the DUAL

TILT mode. When the toggle switch on the dozer control lever is moved

forward, the S2 coil in the solenoid valve is energized and the system

operates in the SINGLE TILT mode. When the trigger switch on the

dozer control lever is depressed, the system energizes the S1 coil in the

solenoid and activates the BLADE PITCH mode.



• Tilt cylinders contain

bypass valvesBoth the left and right tilt cylinders pistons contain bypass valves. These

valves allow the completion of the tilt operation. When one of the

cylinders reaches the end of its travel, the oil goes through the bypass

valve to continue filling the other cylinder.

STMG 692 - 34 -

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STMG 692 - 35 -

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24

• Dual tilt operation

• DUAL TILT RIGHT

• Cylinders move in

opposite directions

FROM TILT

CONTROL VALVE

TO TILT

CONTROL VALVE FROM FAN

PUMP

FROM TRIGGER SWITCH

FROM TOGGLE SWITCH

LEFT TILT

CYLINDER

RIGHT TILT

CYLINDERTO HEAD END

TO ROD END

DUAL TILT CIRCUITDUAL TILT RIGHT

When the toggle switch on the dozer control lever is in the rear (OFF)

position and the trigger switch is not depressed, neither coil in the

solenoid valve is energized. The control valve is operating in the DUAL

TILT mode. In the DUAL TILT mode, oil flow is blocked at the solenoid

valve and the dual tilt directional spool remains centered by the spring

force.

When the operator moves the dozer control lever to the TILT RIGHT

position, pump oil from the dozer control valve tilt circuit is sent to the

head end of the left tilt cylinder. This condition causes oil from the rodend of the left tilt cylinder to be forced back to the dual tilt control valve.

The oil travels around the spool and is directed to the rod end of the right

tilt cylinder. As the right tilt cylinder retracts, the oil in the head end of

the cylinder is directed back through the dual tilt control valve and the

dozer tilt control valve to the tank. Movement of the tilt cylinders in

opposite directions causes the blade to tilt.



STMG 692 - 38 -

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26

• Trigger switchenergizes S1 coil

• BLADE PITCHFORWARD

FROM TILT

CONTROL VALVE

TO TILT

CONTROL VALVE

LEFT TILT

CYLINDER

RIGHT TILT

CYLINDERTO HEAD END

TO ROD END

FROM FAN

PUMP

FROM TRIGGER SWITCH

FROM TOGGLE SWITCH

DUAL TILT CIRCUITBLADE PITCH FORWARD

To change the blade pitch, the trigger switch on the dozer control lever is

depressed and the S1 coil in the solenoid valve is energized. The valve

allows pilot oil from the solenoid valve to be directed to the lower end of

the directional spool and opens the upper end of the spool to drain. The

valve spool then shifts up against the spring force to the BLADE PITCH

mode.

For BLADE PITCH FORWARD, flow from the dozer tilt circuit is sent to

the head end of the left tilt cylinder. As the cylinder extends, oil from the

rod end is pushed back to the dual tilt valve and is directed to the head endof the right tilt cylinder. The oil in the rod end of the right tilt cylinder is

pushed back through the dual tilt valve to the hydraulic tank. As both tilt

cylinders extend, the blade pitches forward. The cylinder extension rate is

not the same between the left and right tilt cylinders. This difference is

caused by the unequal volume of oil entering the left cylinder head end

and the volume being pushed from the left cylinder rod end. The left rod

end displaces a volume equivalent to the volume entering the left head

end of the cylinder minus the cylinder rod volume.



• BLADE PITCH haspriority

Since the right tilt cylinder head end receives oil from the rod end of the

left cylinder, the right cylinder will extend at a slower rate than the left

cylinder.

When the dozer control lever is released, the oil is blocked at the control

valve and the blade remains pitched forward until the control lever is

moved again.

One additional characteristic of the BLADE PITCH mode is that the

trigger switch has priority over the toggle switch. Therefore, if the trigger

switch is depressed while the machine is operating in the SINGLE TILT

mode, the S2 coil for single tilt is de-energized and the S1 coil for the

blade pitch is energized. This feature ensures that the BLADE PITCH

can always be changed, regardless of the toggle switch position.

STMG 692 - 39 -

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27

CONCLUSION

This presentation has discussed the major features of the implement

hydraulic system for the D11R Track-type Tractor equipped with the

3508B engine. When used in conjunction with the service manual for this

tractor, the information in this package should help the servicemancorrectly diagnose a problem in the implement hydraulic system.

For service repairs, adjustments, and maintenance, refer to the Operation

and Maintenance Manual, Service Manual, and other related service

publications.

STMG 692 - 40 -

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1. Model view

2. Component locations

3. Hydraulic tank

4. Dozer control valve (component locations)5. Dozer tilt spool (HOLD)

6. Dozer tilt spool (TILT RIGHT)

7. Dozer lift spool (HOLD)

8. Dozer control valve (HOLD)

9. Dozer lift spool (RAISE)

10. Dozer control valve (HOLD)

11. Quick-drop valve (RAISE)

12. Quick-drop vale (LOWER)

13. Quick-drop valve (QUICK-DROP)

14. Quick-drop valve (LOWER WITH /DOWN

PRESSURE)15. Fan drive hydraulic system

16. Ripper valve

17. Ripper and pilot systems (RAISE)

18. Ripper and pilot systems (LOWER)


20. Ripper and pilot systems (SHANK IN)


22. Pilot system (TILT RIGHT)

23. Dual tilt valve (HOLD)

24. Dual tilt valve (DUAL TILT RIGHT)25. Dual tilt valve (SINGLE TILT RIGHT)

26. Dual tilt valve (PITCH FORWARD)

27. Model view

SLIDE LIST

STMG 692 - 41 -

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D U A L T I L T

C O N T R O L V A L V E

Q U I C K - D

R O P

V A L V E S

R I P P E R

C O N T R O L V A L

V E

H Y D R A U L I C

T A N K

P I L O T V A L

V E

A N D D O Z E

R


I M P L E M E N T

P U M P

F A N M O T O R A N D

M A K E U P V A L V E

O I L C O O L E R A N D

B Y P A S S V A L V E

F A N

P

U M P S

I M P

L E M E N T H Y D R A U L I C S Y S T E M C O

M P O N E N T S

STMG 692 - 42 - Serviceman's Handout No. 1

10/97



F R O M S M A L L P U M P

F R O M L A R G E P U M P

F R O M P I L O T V A

L V E

R O D E N D L I F T C Y L I N D E R

H E A D E N D L I F T C Y L I N D E R

R O D E N D

T I L T C Y L I N D E R

H E A D E N D


L I F T

S P O O L

L I F T R E L I E F

V A L V E

T I L T

S P O O L

D O Z E R C

O N T R O L V A L V

E

H O L D


10/97



A

A

S E C T I O N A - A



F R O M P I L O T V

A L V E

D O Z E R T I L T S P O O L

H O L D

T I L T R I G H T

T I L T L E F T


10/97



A

A

S E C T I O N A - A

D O Z E R

T I L T S P O O L

T I L T R I G H T

T I L T R I G H T

T I L T L E F T



F R O M P I L O T V

A L V E


10/97



R O D E N D L I F T C Y L I N D E R

H E A D E N D L I F T C Y L I N D E R

D O Z E R C O N T R O L V A L V E

H O L D

R O D E N D


H E A D

E N D

T I L T C Y L

I N D E R

L I F T S P O O L

L I F T R E L I E F

V A L V E T

I L T

S P O O L

D U M P

V A L V E



F R O M P I L O T V A L V E


10/97



Q U I C K - D R O P V A L V E

R

A I S E

R O D E N D O I L

H E A D E N D O I L


10/97



Q U I C K - D R O P V A L V E

Q U I C

K - D R O P

R O D E N D O I L

H E A D E N D O I L


10/97



Q U I C K - D

R O P V A L V E

L O W E R W I T H

D O W N P R E S S U

R E R

O D E N D O I L

H E A D E N D O I L


10/97



F

A N

P U

M P S

S O L E N O I D

T A N K

F A N

D R I V E

M O

T O R

R A D I A T O R

O I L C O O L E R

O I L

C O O L E R

B Y P A S S

V A L V E

F A N

D R I V E

H Y D R A U L I C S Y S T E M

T O P I L O T V A L V E S


10/97



R I P P E R T I P

S P O O L

R I P P E R L I F T

S P O O L

L I F T

C Y L I N

D E R S


F O R H E A D E N D

O F L I F T

C Y L I N D E R S

L O A D

C H E C K

V A L V E

R I P P E R

A N D

P I L O T S Y S T E M S

R A I S E

F R O M

F A N P U M P

T O D O Z E R

C O N T R O L V A L V

E

T O S H U

T T L E

V A L V E


10/97



T I P

C Y L I N

D E R S

R I P P E R T I P

S P O O L

R I P P E R L I F T

S P O O L


F O R H E A D E N D

O F L I F T

C Y L I N D E R S

L O A D

C H E C K

V A L V E

R I P P E R

A N D

P I L O T S Y S T E M S

S H A N K I N

F R O M

F A N P U M P

T O D O Z E R

C O N T R O L V A L V

E


10/97



P I L O T S Y S T E M

B L A D E T I L T R I G H T

F R O M

F A N P U M P

R I G H T

T I L T

C Y L I N D E R



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S 1

S 2

D U

A L T I L T V A L V E

T I L T

C Y L I N D

E R S

P I L O T O I L F R O M

F A N P U M P

F R O M B L A

D E

T I L T V A L V E

H O L D

T O H E A D

E N D

T O R O D E N D


10/97



F R O M T I L T


T O T I L T


F R O M F A N P U M P

F R O M T R I G G E R

S W I T C H

F R O M T O G G L E S W I T C H

L E F T T I L T

C Y L I N D E R

R I G H T T I L T

C Y L I N D E R

T O H E A D E N D

T O R O D E N D

D U A L T I L T C I R C U I T

S I N G L E T I L T R I G H T


10/97



F R O M T I L T


T O T I L T


L E F T T I L T

C Y L I N D E R

R I G H T T I L T

C Y L I N D E R

T O H E A D E N D

T O R O D E N D

F R O M F A N

P U M P

F R O M T R I G G E R S W I T C H

F R O M T O G G L E S W I T C H

D U A L T I L T C I R C U I T

B L A D E P I T C H F O R W A R D


10/97

d10r implement systems

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