EN CAT Backhoe Loader 420E Hydraulic Schematic Manual - PDF DOWNLOAD

KENR7658-01 October 2008

420E and 430E Backhoe Loader Hydraulic System 420E: PRA1-UP PHC1-UP

430E: SCD1-UP RLN1-UP

© 2008 Caterpillar, All Rights Reserved

Printed in U.S.A.

Component Table ITEM

NAME

PART NUMBER

1

PUMP GP.

267-2755

2

HYDRAULIC TANK

297-1233

3

TANK GROUP

297-1232

4

HYDRAULIC COOLER

304-7847

5

FILTER

226-9747

6

HMU

210-6240

7

FRONT

STEER CYLINDER 214-5097

LIFT CYLINDERS 8A

ST

8B

PL/IT

228-3509 228-3505

TILT CYLINDERS 9A

ST

200-7128

9B

PL/IT

192-3884

10

MP BUCKET CYL.(OPT)

185-1839

STABILIZER CYLINDERS 11A

LH

11B

RH

12

BOOM CYLINDER

13

STICK CYL.

14

SWING CYL.

15

BUCKET CYL.

16

E-STICK CYL (OPT).

262-7049 262-7050 268-9050(S) 210-7076 210-7091(S) 278-1971 210-7095(S) 210-7097(S)

VALVE PILOT 2-BANK 17A

VALVE PILOT-BODY

223-4713

17B

LEVER W/DTNT & SWTCH (OPT)

223-4715

18

ACCUMULATOR

226-0420

19

RIDE CNTRL VALVE (OPT)

245-8780

20

RIDE CNTRL ACCMLTR (OPT)

162-3960

21

RIDE CNTR PRES. SWTCH(OPT)

304-5696

22

TEMP. SENSOR (OPT)

23

DIFF. PRES. SWITCH (OPT)

134-0404

25

COUPLER VALVE (Volume 2)

231-2615

26

COUPLER CYLINDER (Volume 2)

N/A

190-3085

LOADER VALVE (ST) 27

2 BANK

266-2552

27

3 BANK

266-2553

27A

INLET SECTION

269-1080

27B

LIFT SECTION

269-1091

27C

TILT SECTION

269-1092

27D

AUX SECTION

269-1093

27E

OUTLET MANIFOLD

269-1079

LOADER VALVE (PL/IT) 28

3 BANK

266-2563

28B

LIFT SECTION

269-1081

28C

TILT SECTION

269-1082

28D

AUX SECTION

269-1083

SCHEMATIC

LOCATION

Component Table Continued ITEM

NAME

PART NUMBER BACKHOE VALVE (CP)

29

6 BANK

266-2556

29

7 BANK

266-2557

8 BANK

266-2558

BOOM SECTION

269-1062

29 29A 29B

SWING SECTION

269-1064

29C

BUCKET SECTION

269-1065

29D

STICK SECTION

269-1063

29G

E-STICK SECTION

269-1066

29H

RH STABILIZER SECTION

269-1061

29E

AUX SECTION

269-1067

29F

OUTLET MANIFOLD

269-1059

29J

INLET MANIFOLD

269-1060

29K

PATTERN SWITCHING VALVE

257-7724

29L

LH STABILIZER SECTION

269-1061

SCHEMATIC

BACKHOE VALVES (COMMON) 30

VALVE GP - CUSHION RELIEF

206-3685 (STD)

31

VALVE GP - PILOT (BACKHOE)

267-2758

32

VALVE GP - PILOT (LOADER)

267-2758

33

MANIFOLD - PILOT

268-0094

LOCATION

Pressure Tap Table

TAP LOCATIONS Tap T1 T2 T3 SOS

Description Pump Discharge Load Sense Pilot Pressure Oil Sampling

Schematic

Location

FLUID POWER SYMBOLS BASIC COMPONENT SYMBOLS

MAIN AUX.

PUMP or MOTOR

TWO POSITION

HYDRAULIC PNEUMATIC ENERGY TRIANGLES

ATTACHMENT

LINE RESTRICTION

VARIABLE and PRESSURE COMPENSATED

VALVE PORTS

TWO-WAY

THREE POSITION

PUMP: VARIABLE and PRESSURE COMPENSATED

2-SECTION PUMP

VALVES

VALVE ENVELOPES

ONE POSITION

LINE RESTRICTION (FIXED)

RESTRICTION

PRESSURE COMPENSATION

LINE RESTRICTION (VARIABLE)

SPRING (ADJUSTABLE)

VARIABILITY

CONTROL VALVES

SPRING

FLUID CONDITIONER

FOUR-WAY

THREE-WAY

CONTROL VALVES

CHECK VALVES

AB

AB

P T SHIFTED POSITION

P T NORMAL POSITION

INFINITE POSITION

SHUTTLE

SPRING LOADED

BASIC SYMBOL

PILOT CONTROLLED

FLUID STORAGE RESERVOIRS

VENTED

RETURN ABOVE FLUID LEVEL

PRESSURIZED

RETURN BELOW FLUID LEVEL

MEASUREMENT

PRESSURE

TEMPERATURE

ROTATING SHAFTS

FLOW

UNIDIRECTIONAL

BIDIRECTIONAL

COMBINATION CONTROLS

SOLENOID or MANUAL

SOLENOID

SERVO

SOLENOID and PILOT or MANUAL

SOLENOID and PILOT

DETENT

THERMAL

MANUAL CONTROL SYMBOLS

MANUAL SHUTOFF

PUSH-PULL LEVER

RELEASED PRESSURE

EXTERNAL RETURN

PUSH BUTTON

PILOT CONTROL SYMBOLS

INTERNAL RETURN

ACCUMULATORS

SPRING LOADED

GAS CHARGED

HYDRAULIC PUMPS FIXED DISPLACEMENT

GENERAL MANUAL

VARIABLE DISPLACEMENT NON-COMPENSATED

PEDAL

REMOTE SUPPLY PRESSURE

SIMPLIFIED

CROSSING AND JOINING LINES

LINES CROSSING

LINES JOINING

VARIABLE DISPLACEMENT NON-COMPENSATED

UNIDIRECTIONAL

UNIDIRECTIONAL

BIDIRECTIONAL

BIDIRECTIONAL

INTERNAL SUPPLY PRESSURE

COMPLETE

HYDRAULIC AND PNEUMATIC CYLINDERS

SINGLE ACTING

DOUBLE ACTING

INTERNAL PASSAGEWAYS

HYDRAULIC MOTORS FIXED DISPLACEMENT

SPRING

INFINITE POSITIONING

FLOW IN ONE DIRECTION

THREE POSITION

PARALLEL FLOW

CROSS FLOW

TWO POSITION

FLOW ALLOWED IN EITHER DIRECTION

ELECTRICAL SYMBOLS Hydraulic Symbols (Electrical)

M

G Transducer (Fluid)

Transducer (Gas / Air)

Pressure Switch (Adjustable)

Pressure Switch

Generator

Electric Motor

Electrical Wire

Temperature Switch

Electrical Symbols (Electrical)

T

Pressure Symbol

Temperature Symbol

Level Symbol

Flow Symbol

Wire Number Identification Codes

Electrical Schematic Example

Hydraulic Schematic Example Current Standard

Current Standard Harness identification code This example indicates wire 135 in harness "AG".

Wire

Circuit Number Identification

Wire Color

325-AG135 PK-14 325-PK

Circuit Identification Number

Wire Color

Wire Gauge

Previous Standard Wire Color

Wire

325-PK-14 B Circuit Number Identification

A

Wire Gauge (EXAMPLE VALVE)

8

7

6

5

4

12

2

1

BOOSTED BRAKES (REF)

14 11B

3

15

13

16

33

11A

TO REAR AXLE LEFT WHEEL BRAKE

F

F LEFT BRAKE PEDAL

29

TO REAR AXLE

29D

RIGHT WHEEL BRAKE

BACKHOE VALVE RIGHT BRAKE PEDAL

BS

BT

18

E

E

STAB RH

29J

29H

BOOM

STICK

SWING

29A

BUCKET

29B

E-STICK

AUX.

29G

29C

STAB LH

29E

29L

29F

29K

D

D

20 STABILIZER JOYSTICK

21

LEFT JOYSTICK

RIGHT JOYSTICK

19

27A

T3

17C 17A

31

31 C

C

27B DEL

LIFT

8A

9A

T2 33

1

27C TILT

22 SOS

B

T1

5

HYDRAULIC CIRCUIT COLOR DESCRIPTIONS

B

IMPLEMENT and STEERING PUMP CIRCUIT PILOT OIL CIRCUIT BOOSTED BRAKE OIL CIRCUIT LOAD SENSE CIRCUIT

27D

23

SUPPLY LINE DRAIN / RETURN LINE STEERING CYLINDER CIRCUIT LIFT CYLINDER CIRCUIT TILT CYLINDER CIRCUIT

AUX

10

AUXILIARY CIRCUIT (LOADER VALVE)

LOADER VALVE

4

6

SWING CYLINDER CIRCUIT BUCKET CYLINDER CIRCUIT

PUMP

27E

27

STABILIZER CYLINDER CIRCUIT BOOM CYLINDER CIRCUIT STICK CYLINDER CIRCUIT

E-STICK CYLINDER CIRCUIT AUXILIARY CIRCUIT (BACKHOE VALVE)

LINE PATTERNS Pressure Line Pilot / Load Sensing Pressure

3

Drain / Return Lines Component Group

2

A

A

Attachment

HMU

Air Line

FRONT STEER CYL.

CALLOUTS

7

TANK

YY

Taps (Pressure,

52

Components by

Sampling,Sensor) by letter

number

THIS SCHEMATIC IS FOR THE 420E BACKHOE LOADER VOLUME 1 of 2

(ST)

PART NUMBER: 297-5426, CHANGE: 01, VERSION: -

Components are shown installed on a fully operable machine.

Refer to the appropriate Service Manual for Troubleshooting, Specifications and Systems Operations.

8

7

6

5

4

3

2

1

8

7

6

5

4

3

2

1

BOOSTED BRAKES (REF)

14 11B

12

15

33

13

16

TO REAR AXLE LEFT WHEEL BRAKE

11A

F

F

LEFT BRAKE PEDAL

TO REAR AXLE RIGHT WHEEL BRAKE

29

29D

RIGHT BRAKE PEDAL

BACKHOE VALVE

BS

BT

18

E

E

STAB RH

29J

29H

BOOM

STICK

SWING

29A

BUCKET

29B

E-STICK

29C

AUX.

29G

STAB LH

29E

29L

29F

29K

D

D

20 STABILIZER JOYSTICK

21

LEFT JOYSTICK

RIGHT JOYSTICK

19

27A

T3

31

31

17C 17B 17A

C

C

DEL

LIFT

8B

28B

LOADER JOYSTICK

9B

32

33

T2

RTD

FLOAT

1

TILT

B

28C

22

10

HYDRAULIC CIRCUIT COLOR DESCRIPTIONS

SOS

IMPLEMENT and STEERING PUMP CIRCUIT PILOT OIL CIRCUIT

5

T1

BOOSTED BRAKE OIL CIRCUIT LOAD SENSE CIRCUIT SUPPLY LINE DRAIN / RETURN LINE STEERING CYLINDER CIRCUIT LIFT CYLINDER CIRCUIT TILT CYLINDER CIRCUIT

23 AUX

AUXILIARY CIRCUIT (LOADER VALVE)

28B LOADER VALVE

STABILIZER CYLINDER CIRCUIT BOOM CYLINDER CIRCUIT STICK CYLINDER CIRCUIT

4 6

SWING CYLINDER CIRCUIT BUCKET CYLINDER CIRCUIT

PUMP

27E

28

B

E-STICK CYLINDER CIRCUIT AUXILIARY CIRCUIT (BACKHOE VALVE)

LINE PATTERNS Pressure Line

26

25

Pilot / Load Sensing Pressure Drain / Return Lines

3

Component Group

A

A

Attachment

2

Air Line

HMU FRONT STEER CYL.

CALLOUTS

TANK

7

YY

Taps (Pressure,

52

Components by

Sampling,Sensor) by letter

number

THIS SCHEMATIC IS FOR THE 420E BACKHOE LOADER VOLUME 2 of 2

( PL / IT )

PART NUMBER: 297-5426, CHANGE: 01, VERSION: -

Components are shown installed on a fully operable machine.

Refer to the appropriate Service Manual for Troubleshooting, Specifications and Systems Operations.

8

7

6

5

4

3

2

1

Hydraulic Components - Chassis View

13

12

30

29

11A

31

33

5

6

3

2

8

4

9

10

26 25 16 15

14

14

11B

17

32

18

28

1

19

20

8

7

9

10

Backhoe Valve (8 Bank) For other bank valve configurations see RENR6487 (Specifications Manual).

29F

29L

29C

29G

29C 29B

29D

29A

29H J

L

M

29J

EIGHT BANK VALVE (PILOT OPERATED) (29F) Outlet Manifold (29L) Left Stabilizer Control Valve (29E) Auxiliary Control Valve (29G) Extendable Stick Control Valve (29C) Bucket Control Valve (29B) Swing Control Valve (29D) Stick Control Valve

(29A) Boom Control Valve (29H) Right Stabilizer Control Valve (J) Pilot On/Off Solenoid Valve (29J) Inlet Manifold (L) A Ports (M) B Ports

Implement and Steering Pump B

1

A

T2

27

D

T1

C

E G C

T2

H A

T2 B Drain

T1 E D

C

F

These illustrations show the implement and steering pump (1) out of the machine. The following components are visible: Torque control adjustment (A), Flow compensator adjustment (B), Load sensing pressure tap (T2), Inlet port (C), Case drain port (D), Torque control solenoid (E), Discharge pressure tap (T1), Torque limiter (F), Outlet port (G), Loader Valve (27).

The implement and steering pump on the 420E/430E machines are similar to the "D" Series machines, but now includes a torque control solenoid (not visible). The torque control solenoid provides an additional pump setting.

The implement and steering pump is located below the floor plate in the cab. The pump control valve (H) contains a torque control spool adjustment screw (B) and a flow compensator adjustment screw (A). The adjustment screws and the load sensing pressure tap (T2) are accessible from the cab.

Hydraulic Oil Filter Temp Sensor

SOS

Filter Bypass Switch

Temp Sensor

Filter Bypass Switch

SOS

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.

Loader Valve

SOS

1 5 Three Bank (Mechanically Controlled)

27B 27C 27

G

H

28C

J

28B

L

K

27A

The loader valve is accessed from below the floor plate. The loader control valve group contains:

28D 27E

28

P R N

27A

27D

M

F

(27E) Outlet manifold (27D, 28D) Auxiliary control valve (27C, 28C) Tilt control valve (27B, 28B) Lift control valve (27A) Inlet manifold (F) Load sensing relief valve (G) Solenoid for the B circuit (H) Solenoid for the A circuit (J) Makeup and relief valve (K) B pilot line port (L) A pilot line port (M) Priority Valve (N) Dead engine lower valve (P) A ports (R) B ports

THREE BANK VALVE (PILOT OPERATED)

NOTE: Machines with a mechanically controlled loader valve or a pilot controlled loader valve use the same inlet manifold.

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

Ride Control (Option) Ride Control Solenoids

Ride Control Relay

21

19

20

ECM

Travel at high speeds over rough terrain causes bucket movement. The optional Ride Control System acts as a shock absorber by absorbing bucket forces, which stabilize the machine.

The Ride Control System components include; Ride Control Valve (19), Ride Control Relay, Ride Control Solenoids, Ride Control Accumulator (20), and Ride Control Pressure Switch (21).

Two solenoids are now used on the "E" Series machines Ride Control System.

The Ride Control System, on machines with the optional autoshift transmission, is controlled by the Machine ECM. The Machine ECM monitors the position of the ride control switch and determines when to operate the ride control system.

Boosted Brakes To Wheel Brake

Slave Cylinder

To Tank

From Pilot Accumulator

Master Cylinder

Boost Brake Valve

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.

A

E

D

C

B

The 420E/430E machines are equipped with hydraulically assisted master cylinders. The brake boost valves are connected to the master cylinder (A) at each brake pedal (B). Oil enters the master cylinder through the supply hose (C) and exits the master cylinder through the return hose (D). The oil flows to the service brakes through the hoses (E) at the bottom of the master cylinder. The master cylinders can be removed from the machine from inside the operator's compartment.