©2003 CaterpillarAll Rights Reserved

Printed in U.S.A.

RENR4398-02August 2003

966G Series II Wheel Loader and

Hydraulic SystemAWY1-UPAXC1-UP

AXJ1-UPAXN1-UP

ANT1-UPANY1-UP

ANZ1-UPAWP1-UP

972G Series II Wheel Loader

AXL1-UP AXP1-UPAXE1-UP AWZ1-UP

A

B

C

D

E

F

G

1 2 3 4 5 6 7

A

B

C

E

F

G

7654321

1 2 4 5

AA

BB CC

DD

6 7 8 9 10 11 123

FF

GG

HH

14 15

16 17 18 19 20

21 22 23 24

KK

MM

26

25

29 30

49 50 51

27

D

13

28

ItemNo. Component

12

3

45

6789

1011

SchematicLocation

121314151617

1819

2021

22232425

26

SchematicLocation

AABB

CCDD

ItemNo. Component

SchematicLocation

PressureTap Description

2728

29

3031

323334

* Secondary Steering is an optional attachment.

FFGG

HHJJ

A3

# Ride Control is an optional attachment.

A7

35

373839

40

41424344

45

Steering Cylinders

Steering Backup Relief Valve F5

46

47

Chart A Chart A

Tilt CylinderAuxiliary Cylinders @

Lift CylindersFront Service BrakesLeft Pedal AssemblyRight Pedal AssemblyService Brake Control ValveFront Service Brakes Accumulator

Rear Service Brakes AccumulatorParking BrakeParking Brake ActuatorOrifice

Ride Control Accumulator #Main Relief ValveLine Relief Valve (Aux. Cylinder Head End) @

Line Relief Valve (Aux. Cylinder Rod End) @Line Relief Valve (Tilt Cylinder Rod End)Line Relief Valve (Tilt Cylinder Head End)Rear Service BrakesAccumulator Charging ValveParking Brake Control Valve

Parking Brake Pressure Switch

Service Brake Oil Pressure SwitchPilot Valve (Oil Manifold)

Hydraulic Oil Filter

Hydraulic Oil Cooler Bypass ValveHydraulic Oil Cooler

Secondary Steering Valve *Left Steering Neutralizer ValveRight Steering Neutralizer Valve

36

Steering Pump

Implement Pump

Breaker Relief Valve

Fan Drive Pump

Fan Drive Motor

Secondary Steering Pump and Electric Motor*

Steering Control ValveSteering Crossover Relief Valve

Hydraulic Oil Tank

Tilt Cylinder Rod End PressureTilt Cylinder Head End PressureRear Service Brake PressureFront Service Brake PressureService Brake Accumulator PressureImplement Pilot Pump Pressure

Implement Pump PressureFluid Sampling Valve

KK

LL

MM

Steering Pump Pressure

Fan Drive Pump Pressure

Steering Signal Pressure

A1A2

A4

A5

A6

A3A4A5A1

A2

A3B5B6

B7

C6C1

C3

D5

D7

F3F4

F6

A5

C6

C4D1

E5

F4

Pilot/Brake Pump

A3

Ride Control Diverter Valve #

Pilot Control Valve

Main Control Valve %

The three stem valve is an optional attachment.

@ Auxiliary Cylinders are an optional attachment.

% The one stem valve (third function) is an

The two stem valve is standard.optional attachment field conversion.

48

49

505152 Brake Oil Cooler

Screen Group

F2

F1

Flow Divider Valve (Brake Oil Cooler)E2

Ball Valve (Hydraulic Lever Lock)

Check ValveCheck Valve C1

B4

Chart B

Steering Metering Pump

1,

AA, BBFF, MM

2

36, 7

1, 3

25

CC, DD, MM 13 - 20,

HH

421

48

28, GG

9, 10,49, 50,51, KK

2722 - 24,

11, 12

6, 7JJ

29, 30

29, 30 8, 9,

CC, DD, 10, 48, 13 - 20, 28

JJ

5

4GG

21

27

49, 50,51, KK

11, 12

HH

22 - 24,

187-6676-00

966G II & 972G II PILOT IMPLEMENT/STEERING METERING PUMP HYDRAULIC SCHEMATIC

3132 33 34

35

36 37

38

39

40 41

47

48

44 45 46 43

966G II and 972G II Hydraulic Pressure Tap Locations

966G II and 972G II Hydraulic Component Locations 966G II and 972G II Hydraulic Component Locations

F2D4

D4

Electro-Hydraulic Control

E2E1E3

E2

53 F2

52 52

53

4243

36, 37 41, LL 32, 37 FF 8, 33, 37,

31

38

39, 44, 45 43, 53,

34, 35

38, LL

31

32, 47

39, 44, 45

40,42 - 48

36, 3743, 53,

3533, 34

JJ

LL

E3

E2

A

A

B

B

SECONDARY STEERING SUCTION

C P

TX

B

S L1

PILO

T/BR

AKE

IMPL

EMEN

T

STEERING

STEERING LOAD SENSE SIGNAL

STEERING RETURN

IMPLEMENT PILOT/PILT STEERING RETURNIMPLEMENT RETURN

TOBRAKEDRAIN

AUX LIFT

TILT

LOW

ER/C

LOSE

OPE

N/R

AISE

TILT

BAC

K

DU

MP

LOW

ER

RAI

SE

TOTRANSMISSION

CONTROLTO BRAKE

LIGHTS

TOTRANSMISSION

CONTROL

F06057

A

966G SERIES II

AXJ636-UPANT1-UPANZ1-UP

AWY431-UP

972G SERIES IIAXC526-UPAXN253-UPANY1-UPAWP1-UP

NOT USED ON THETHE RELIEF VALVE IS

FOLLOWING MACHINES:

Pilot Pressure

LINEAR PATTERNS

Return Lines

Pressure

Components

Denotes Wire Code

A

B

C

D

E

F

G

1 2 5 6 7

A

B

C

D

E

F

G

7654321

1 2 3 4 7 8 9 10 11 12

14 15

181716 19 20

21 22 23

E4

E1

E2

E3 E5

E6

E7

AA

BB

CC

DD

LL

MM

NN

PP

UU

VV

SS

WW

ZZ

EE FF GG HH JJ KKLL

NN

25

27

24

29

31

40 41

34

35

36

33

13

26

28 30

393837

32

ItemNo. Component

12

3

45

6789

1011

SchematicLocation

1213

1415

1617

1819

2021

2223

2425

26

SchematicLocation

AABB

CC

DD

ItemNo. Component

SchematicLocation

PressureTap Description

* Secondary Steering is an optional attachment.

A3

# Ride Control is an optional attachment.

A7

Steering Cylinders

Tilt CylinderAuxiliary Cylinders @

Lift CylindersFront Service BrakesLeft Pedal AssemblyRight Pedal AssemblyService Brake Control ValveFront Service Brakes Accumulator

Rear Service Brakes AccumulatorParking BrakeParking Brake ActuatorOrifice

Ride Control Accumulator #Main Relief ValveLine Relief Valve (Aux. Cylinder Head End) @

Line Relief Valve (Aux. Cylinder Rod End) @Line Relief Valve (Tilt Cylinder Rod End)Line Relief Valve (Tilt Cylinder Head End)Rear Service BrakesAccumulator Charging Valve

Service Brake Oil Pressure Switch

Hydraulic Oil Filter

Left Steering Neutralizer Valve

Breaker Relief Valve

Secondary Steering Pump and Electric Motor*

Steering Control ValveSteering Crossover Relief Valve

Tilt Cylinder Rod End Pressure

Tilt Cylinder Head End PressureRear Service Brake PressureFront Service Brake Pressure

Service Brake Accumulator Pressure

A1A2

A4

A5

A6

A3

A5

A1

A2

A3

B5

B6B7

A5

A3

Ride Control Diverter Valve #

Main Control Valve %

The three stem valve is an optional attachment.

@ Auxiliary Cylinders are an optional attachment.% The one stem valve (third function) is an

The two stem valve is standard.optional attachment field conversion.

Pilot Valve (Oil Manifold)27

Parking Brake Pressure Switch

Lowering Control Valve

Parking Brake Control Valve

Steering Pilot ValveSteering WheelManifold (Orifice and Screen)OrificeScreen

Check Valve

Shuttle Valve

Implement Pump Pressure

EE

FF

GGHH

JJ

KK

LL

MM

NNPP

Pilot Pump Pressure

Auxiliary Pilot Pump PressureAuxiliary Pilot Pump Pressure

Tilt Pilot Pump PressureTilt Pilot Pump Pressure

Lift Pilot Pump PressureLift Pilot Pump Pressure

Steering Pilot Pressure

Steering Pilot Pressure

Steering Pilot Pressure

Steering Control ValveNeutral Pilot Pressure

C1

C6C7

D7

D5D4

D5

E5

E6

E7

E2

E1

F5

F6

F7

B1

B2

B3

C4

C5C6D1E2

E6

E3

E4

F4

F6

Chart C

Fluid Sampling ValveSteering Pump Pressure

RRSS

TT

UU

VV

WW

Fan Drive Pump Pressure

ZZ Steering Signal Pressure F5

6059

58575655

54535251

5049

F2Brake Oil CoolerF4

4847

4645

44

434241

4039

383736

3534

33

3231

282930

Screen GroupCheck ValveCheck Valve C4

Implement Pump

Flow Divider Valve (Brake Oil Cooler)

E2

Fan Drive Pump

Hydraulic Oil CoolerFan Drive Motor

Shuttle Valve F4Secondary Steering Valve *Right Steering Neutralizer ValvePressure Reducing Valve

Steering Backup Relief ValveSteering PumpPilot/Brake PumpScreen Group

F1

4

GG 2

3

6, 7

1,

2521 4

NN 3

13 - 20,22, 23,29, 30

8, 31, 38 CC, DD 24, 25, 27,

EE, FF, GGHH, JJ, KKLL, UU, VV

6, 7, 26, 31, 11, 1232, 37

SS, WW

39, 40, 41,34, 35, 36,

9, 10,42, MM

5, 59NN

21, 5911, 12

1, 13 - 20,24, 25, 27, 28,

HH, JJ, KK,LL, UU, VV

AA, BB

32, 37MM, PP, ZZ

8, 9, 10, 26

33

22, 23,29, 30

4234, 35, 36, 39,

43, 47

43, 47F06027 187-6676-00

966G II & 972G II E/H IMPLEMENT/COMMAND CONTROL STEERING HYDRAULIC SCHEMATIC

TT

RR

26

61

Hydraulic Oil Tank F161

Chart D966G II and 972G II Hydraulic Pressure Tap Locations

Chart C966G II and 972G II Hydraulic Component Locations 966G II and 972G II Hydraulic Component Locations

42 43 44

45

46

4748

49

50 51 52 53 54

6055 56 57

57

5859 59

Electro-hydraulic control E3

F3F2

E3

Hydraulic Oil Cooler Bypass Valve

47, TT 45, 53, 54

51, 60

28, 50

44

45, 55, 56

57, 5961, RR 52, PP, ZZ

55, 56

51, 6040, 41, 48, 5354, 57, WW

38, 52, CC, DD 50, EE, FF, GG

47, 49, TT

44

57, 59,61, RR

31, 46

E2

TRANSMISSIONCONTROL

BK

RD

BU

RD

BU

TO BRAKELIGHTS

TO

TRANSMISSIONCONTROL

TO

Pilot Pressure

LINEAR PATTERNS

Return Lines

Pressure

Components

Denotes Wire Code

L1S

B

X

P

TC

B A

A

A

B

S

A

966G SERIES II

AXJ636-UPANT1-UPANZ1-UP

AWY431-UP

972G SERIES IIAXC526-UPAXN253-UPANY1-UPAWP1-UP

NOT USED ON THETHE RELIEF VALVE IS

LOWER/CLOSE

OPEN/RAISE

FLOAT

LOWER

RAISE

DUMP

TILT BACK

BRAKEDRAIN

TO

STEERING

STEERING LOAD SENSE SIGNAL

STEERING RETURN

IMPLEMENT RETURN

IMPLEMENT PILOT/PILOT STEERING RETURN

HIGH PRESSURE H.E. OR R.E.

SECONDARY STEERING SUCTIONFAN SUCTION

PILO

T/BR

AKE

IMPL

EMEN

T

LIFT

TILT

AUX

LOW

ER/C

LOSE OPE

N/R

AISE

TILT

BAC

K

DU

MP

LOW

ER

RAI

SE

FOLLOWING MACHINES:

43

65