432E, 434E, 442E, and 444E

Hydraulic SystemBackhoe Loader

HXB1-UPSXB1-UPPCR1-UPRXS1-UP

© 2008 Caterpillar, All Rights Reserved Printed in U.S.A.

KENR8042November 2008

ONE POSITION TWO POSITION THREE POSITION

VENTED PRESSURIZED RETURN ABOVE FLUID LEVEL RETURN BELOW FLUID LEVEL

LINES CROSSING LINES JOINING

TWO - WAY THREE - WAY FOUR - WAY

SPRING CONTROL VALVES RESTRICTION LINE RESTRICTION(FIXED)

PUMP(2 - SECTION)

SPRING(ADJUSTABLE)

VARIABILITY LINE RESTRICTION(VARIABLE)

PRESSURECOMPENSATION

PUMP(VARIABLE & PRESSURE

COMPENSATED)

MEASUREMENT

PRESSURE TEMPERATURE FLOW

ROTATING SHAFTS

UNIDIRECTIONAL BIDIRECTIONAL

PUSH - PULL LEVER PEDALGENERAL MANUAL PUSH BUTTON SPRING

FIXEDDISPLACEMENT

VARIABLE DISPLACEMENTNON-COMPENSATED

UNIDIRECTIONAL

BIDIRECTIONAL

VALVE ENVELOPES VALVE PORTS

FLUID CONDITIONERPUMP OR MOTOR

FLUID POWER SYMBOLS

UNIDIRECTIONAL

BIDIRECTIONAL

RELEASED PRESSURE

EXTERNAL RETURN INTERNAL RETURN

REMOTE SUPPLY PRESSURE

SIMPLIFIED

HYDRAULIC PUMPS

ACCUMULATORS

SPRING LOADED GAS CHARGED

SOLENOID OR MANUAL

SOLENOID & PILOT

SOLENOID &PILOT OR MANUAL

SOLENOID SERVO THERMAL DETENT

HYDRAULIC & PNEUMATIC CYLINDERS

DOUBLE ACTINGSINGLE ACTING

BASICSYMBOL

SPRINGLOADED

CHECK VALVES

2 POSITIONINFINITE

POSITIONING

FLOW IN ONEDIRECTION

FLOW INEITHER

DIRECTION

3 POSITION

CROSSFLOW

PARALLELFLOW

INTERNAL PASSAGEWAYS

NORMAL POSITION

A B

P T

A B

P TSHIFTED POSITION INFINITE POSITION

CONTROL VALVES

ATTACHMENT

MANUAL SHUTOFF

SHUTTLE PILOTCONTROLLED

MAIN AUX

LINE RESTRICTION(VARIABLE & PRESSURE

COMPENSATED)

MANUAL CONTROL SYMBOLS

HYDRAULIC MOTORS

FLUID STORAGE RESERVOIRS

CROSSING & JOINING LINES

VALVES

PILOT CONTROL SYMBOLS

COMBINATION CONTROLS

BASIC COMPONENT SYMBOLS

ENERGY TRIANGLESHYDRAULIC PNEUMATIC

INTERNALSUPPLY PRESSURE

COMPLETE

FIXEDDISPLACEMENT

VARIABLE DISPLACEMENTNON-COMPENSATED

HYDRAULIC SYMBOLS (ELECTRICAL)

ELECTRICAL SYMBOLS TABLE

325-AG135 PK-14

HARNESS IDENTIFICATION CODE THIS EXAMPLEINDICATES WIRE 135 IN HARNESS “AG”

325-PK-14

WIRE GAUGE

WIRE COLOR

CIRCUIT NUMBERIDENTIFICATION

WIRE NUMBER IDENTIFICATION CODES

CURRENT STANDARD

PREVIOUS STANDARD

ELECTRICAL SCHEMATIC EXAMPLE HYDRAULIC SCHEMATIC EXAMPLE

325-PK

WIRE COLORCIRCUIT NUMBER

IDENTIFICATION

B

WIRE

WIRE

(EXAMPLE VALVE)

CURRENT STANDARD

TRANSDUCER(FLUID)

MELECTRIC MOTORTRANSDUCER

(GAS / AIR)

G

GENERATOR

PRESSURE SWITCH ELECTRICAL WIREPRESSURE SWITCH(ADJUSTABLE)

TEMPERATURESWITCH

PRESSURESWITCH

TEMPERATURESWITCH

LEVELSWITCH

FLOWSWITCH

ELECTRICAL SYMBOLS (ELECTRICAL)

A

CIRCUIT NUMBERIDENTIFICATION

WIRECOLOR

WIRE GAUGE

T

KE

NR

8042

30

Pa

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, (D

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s:

39

in

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x 2

8 i

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COMPONENT LOCATIONS

30 3119

14 15

14

2

2

15

3130

19

9

9

67

7

6

13

13

13

34

34

34

8

8

8

10

3

3

10

4

4

1211

11

12

33

33

32

323637

363735

23

23

352518

Tap DescriptionT1 Pump DischargeT2 Load Sense

SOS Oil Sampling

TAP LOCATIONS

BACKHOE VALVE

SOSImplement and Steering Pump

HYDRAULIC OIL FILTER

SOS Filter Bypass Switch

LOADER VALVE

E

DC

B

A

RIDE CONTROL

B

A

C

D

IMPLEMENT / STEERING PUMP

Implement and Steering Pump

F

View of mechanically controlled loader valve with floor plate removed.

Loader Valve

B C D

THREE BANK VALVE (PILOT OPERATED)

G

H J K L

M

P

R

N

E

G

A

B

E

F

D C

D

E

C

AB

T2

T2

T1

T2

T1

C

This illustration shows a sectional view of the boosted brake valve group. When the brake pedal is depressed, the boost brake valve moves to the left and inlet oil from the pilot manifold is directed to the master cylinder.

BOOSTED BRAKES

Drain

SEVEN BANK VALVE

For other bank valve configurations see RENR6487 (Specifications Manual).

For other bank valve configurations see RENR6487 (Specifications Manual).

SIDESHIFT

T3

Pilot Manifold

View of pilot controlled backhoe valve with floor plate removed.

The hydraulic oil filter is located below the machine at the left frame rail. The hydraulic oil filter bypass switch is mounted to the oil filter base.

(A) Outlet manifold (H) Solenoid for the A circuit (B)Auxiliary control valve (J) Makeup and relief valve (C) Tilt control valve (K) B pilot line port (D) Lift control valve (L) A pilot line port (E) Inlet manifold (M) Priority Valve (F) Load sensing relief valve (N) Dead engine lower valve (G) Solenoid for the B circuit (P) A ports

(R) B ports

SOS

ECM

Loader Valve

A

A

B

CD

To Wheel Brake

Boost Brake Valve

From PilotAccumulatorTo Tank

Master Cylinder

SlaveCylinder

A B

T3 Pilot Pressure

9

9

1

25

181

29

29

21

21

26

26

28

28

38

38

24

245 22

5 22

Hydraulic Oil Filter

Temp Sensor

Filter BypassSwitch

Temp Sensor

H

LINE MAKE-UP/RELIEF VALVE

STAB

BOOM

SWING

STAB

BUCKETSTICK

E-STICK

TANK (PLUGGED)GAUGE(PLUGGED)

SIDESHIFT CLAMP SOLENOID VALVE

M14x2

SIDESHIFT CLAMP

M14x2

PUMP (PLUGGED)

TANK (LS DRAIN)

LOAD SENSERELIEF VALVE

LOAD SENSE

(A) Ride Control Relay(B) Ride Control Solenoid(C) Ride Control Accumulator(D) Ride Control Pressure Switch

Description PartNumber

MachineLocation

SchematicLocation

5-C10240-622rotalumuccA2-B27487-403liO-relooC

Cylinder - Boom (432E/434E) 268-9049 (S) 3 F-5Cylinder - Boom (432E/434E) 210-7076 3 F-5Cylinder - Boom (442E/444E) 268-9051 (S) 3 F-5Cylinder - Boom (442E/444E) 246-9884 3 F-5Cylinder - Bucket (432E/434E) 210-7085 (S) 4 F-4Cylinder - Bucket (432E/434E) 210-7086 4 F-4Cylinder - Bucket (442E/444E) 210-7095 (S) 4 F-4Cylinder - Bucket (442E/444E) 210-7096 4 F-4

8-A55803-091relpuoC-rednilyCCylinder - Lift (PL/IT) 214-9373 6 B-8Cylinder - Lift LH (EST 434E) 249-6710 6 B-8Cylinder - Lift RH (EST 434E) 249-6711 7 C-8Cylinder - Lift LH (EST 444E) 249-6712 6 B-8Cylinder - Lift RH (EST 444E) 249-6713 7 C-8Cylinder - Stabilizer 173-4565 8 F-3/F-6Cylinder - Steer (Front) N/A 9 B-6Cylinder - Steer (Rear) N/A 9 B-5Cylinder - Stick (432E/434E) 210-7083 (S) 10 F-4Cylinder - Stick (432E/434E) 210-7084 10 F-4Cylinder - Stick (442E/444E) 210-7093 (S) 10 F-4Cylinder - Stick (442E/444E) 210-7094 10 F-4Cylinder - Swing (LH) 278-1971 11 F-5Cylinder - Swing (RH) 278-1973 12 F-5Cylinder - Tilt (PL/IT) 192-3884 13 B-8Cylinder - Tilt (EST 434E) 210-7101 13 B-8Cylinder - Tilt (EST 444E) 214-9372 13 B-8

2-B417526-523retliF6-A510426-012UMH

Manifold - Inlet (SS 7 bank) 308-2147 16 E-7Manifold - Outlet (SS 7Bank) 308-2154 17 E-2

5-C813944-003VRP-dlofinaM3-B910736-982pGpmuP

Valve - All Wheel Steer (434/444) 256-3089 20 A-4 to A-5Valve - Backhoe (SS) 7 Bank 293-8701 21 E-2 to E-7Valve - Control (Boom SS 7Bank) 308-2149 21 E-5Valve - Control (Bucket SS 7Bank) 308-2151 21 E-4Valve - Control (E-Stick 7Bank) 308-2153 21 E-3Valve - Control (Stick SS 7Bank) 308-2152 21 E-4Valve - Control (Stabilizer 7Bank) 308-2148 21 E-3 / E-6Valve - Control (Swing SS 7Bank) 308-2150 21 E-5

8-A225162-132relpuoC-evlaVValve - Loader (PL/IT) 3 Bank 293-8703 23 A-7 to C-7Valve - Control (Lift PL/IT 3Bank) 308-2157 23 B-7Valve - Control (Tilt PL/IT 3Bank) 308-2163 23 B-7Valve - Control (Aux PL/IT 3Bank) 308-2159 23 A-7Valve - Loader Inlet (PL/IT) 3Bank 308-2162 23 C-7Valve - Loader (EST) 293-8702 24 A-7 to C-7Valve - Control (Tilt EST 3Bank) 308-2158 24 B-7Valve - Loader Inlet (EST 3Bank) 308-2156 24 C-7Valve - Pattern Switching 300-4491 25 D-4Valve - Pilot (Switch) 297-4394 26 C-5Valve - Pilot (Switch + Detent) 297-4395 26 C-5Valve - Stabilizer PO Check 308-3437 27 F-3 / F-6Valve Gp - Pilot (Backhoe) 267-2758 28 C-3 / C-4Valve Gp - Pilot (Loader) 267-2760 29 C-6

2-A036825-642ciluardyH-knaT2-A137778-542pGknaT

Accumulator - Ride Control 162-3960 32 D-8Cylinder - E-Stick 210-7097 (S) 33 F-3

3-F338907-012kcitS-E-rednilyC8-A43A/NtekcuBPM-rednilyC

Sensor - Temperature N/A 35 B-2Switch - Differential Pressure 134-0404 35 B-2Switch - Ride Control Pressure 131-9203 36 C-8Valve - All Wheel Steer (432/442) 256-3089 20 A-4 to A-5Valve - Ride Control 245-8780 37 C-8Valve Gp - Cushion Relief 320-7812 38 F-5

Component Locations

Attachments

(A) Flow Compensator Adjustment Screw(B) Torque Control Spool Adjustment Screw(C) Inlet Port(D) Case Drain Port(E) Torque control Solenoid(F) Torque Limiter(H) Pump Control Valve(T1) Discharge pressure tap(T2) Load Sensing Pressure Tap

(A) Master Cylinder(B) Brake Pedal

(A) Hydraulic Cylinder(B) Wear Pad

(C) Wear Plate(D) Stabilizers

LINE PATTERNS

Drain / Return Lines

Component Group

Pilot / Load Sensing Pressure

Pressure Line

Attachment

Air Line

CALLOUTS

Taps (Pressure, Sampling, Sensor - by letter)YY

HYDRAULIC CIRCUIT COLOR DESCRIPTIONSPILOT OIL CIRCUITIMPLEMENT AND STEERING PUMP CIRCUITLIFT CYLINDER CIRCUITBUCKET CYLINDER CIRCUITLOAD SENSE CIRCUITSTEERING CYLINDER CIRCUITSTICK CYLINDER CIRCUITSUPPLY LINEBOOM CYLINDER CIRCUITTILT CYLINDER CIRCUITAUXILIARY CIRCUIT (LOADER VALVE)DRAIN / RETURN LINESTABILIZER CYLINDER CIRCUITSWING CYLINDER CIRCUITE-STICK CYLINDER CIRCUITSIDESHIFT LOCK CYLINDER CIRCUITBOOSTED BRAKE OIL CIRCUIT

KE

NR

8042

30

Pa

ge

, (D

ime

ns

ion

s:

39

in

ch

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x 2

8 i

nc

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THIS SCHEMATIC IS FOR THE 432E, 434E, 442E, AND 444E BACKHOE LOADERMEDIA NUMBER: KENR8042PART NUMBER: 322-3114, CHANGE: 00, VERSION: SComponents are shown installed on a fully operable machine.

Refer to the appropriate Service Manual for Troubleshooting, Specifications.

12345678

A

B

C

D

E

F

12345678

A

B

C

D

E

F

LOADER VALVE

PT DLS

LS

D

LIFT

a1

B1

A1

a2

B2

A2

TILT

AUX

T2

P

P2

LS

B1 A1 B2 A2 B3 A3 B4 A4 B5 A5 B6 A6 B7 A7

T b1 a1 b2 b3 a3 b4 a4 b5 a5 b6 a6 b1 a1

STAB BOOM BUCKETSWING STICK E-STICK STAB

a2

T1

T3

C

b1

b2

a3

b3

BACKHOE VALVE

M

A3

B3

SWINGCYLINDER

278-1971(LH)278-1973(RH)

CUSHION RELIEFVALVE GROUP(ATCH)320-7812

E-STICK CYLINDER(ATCH)210-7097(S)/210-7098

BOOMCYLINDER

210-7076 (432E/434E)246-9884 (442E/444E)

RIDE CONTROLACCUMULATOR(ATCH)162-3960

RIDE CONTROLPRESSURESWITCH (ATCH)131-9203

RIDE CONTROLVALVE (ATCH)245-8780

INLET SECTION(434E/444E)308-2156

LIFT CYL(PL/IT) 214-9373(EST) 249-6710(LH) 249-6711(RH)

TILT CYL(PL/IT)192-3884

MP BUCKET CYL(ATCH)

COUPLERCYLINDER190-3085

COUPLERVALVE231-2615

HMU210-6240

FRONTSTEERCYLINDER

REARSTEERCYLINDER

ALL WHEELSTEERVALVE256-3089(434E/444E)(ATCH)-256-3089(432E/442E)

TEMPERATURESENSOR(ATCH)

DIFFERENTIALPRESSURESWITCH(ATCH)134-0404

OIL COOLER

FILTER325-6257

PUMP GP289-6370

HYDRAULICTANK

246-5286

TANKGROUP245-8777

INLETMANIFOLD308-2147

STABILIZERSECTION308-2148

STABILIZERCYLINDER173-4565

STABILIZERPO CHECKVALVE308-3437

BUCKET CYLINDER(210-7085(S)/210-7086)(432E/434E)(210-7095(S)/210-7096)(442E/444E)

STICK CYLINDER(210-7083(S)/210-7084)(432E/434E)(210-7093(S)/210-7094)(442E/444E)

STABILIZERPO CHECKVALVE308-3437

STABILIZERCYLINDER173-4565

BACKHOEVALVE (SS)293-8701

OUTLETMANIFOLD308-2154

STABILIZERSECTION308-2150

E-STICKSECTION308-2153

STICKSECTION308-2152

PATTERNSWITCHINGVALVE300-4491

BUCKETSECTION308-2151

SWINGSECTION308-2150

BOOMSECTION308-2149

LOADERVALVE (EST)293-8702

AUX SECTION308-2159

TILT SECTION308-2158

LIFT SECTION308-2157

P6 P5 P7 P8

P1 P2 P3 P4

RR LR

RHMU

b

aLF

T

P

T

PS

R L

LS

PT

B

S L1 L

X

R HAWS ELECTRICALPRESSURE SWITCH

RIGHT JOYSTICK

BOOM BUCKET

PT

1

23

4

LEFT JOYSTICK

STICK SWING

PT

1

2 3

4

STABILIZER LEVERS

LH RH

PT

1

2 3

4

LOADER JOYSTICK

LIFT TILT

1 2 3 4

PT

FLOATELECTRICAL

PRESSURESWITCH

IN

T

T1

T2 A1 A2 B2

P1 P2 P3

T3

B1

ACC

BOOSTED BRAKES (REF)

LEFT BRAKE PEDAL

RIGHT BRAKE PEDAL

TO REAR AXLE

LEFT WHEEL BRAKE

TO REAR AXLE

RIGHT WHEEL BRAKE

T2

T1

T3