KENR9016
November 2008
422E and 428E Backhoe Loader
Hydraulic System
422E:
DSK1-UP
428E:
DXC1-UP
Printed in U.S.A.© 2008 Caterpillar, All Rights Reserved
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)
PRESSURE
COMPENSATION
PUMP
(VARIABLE & PRESSURE
COMPENSATED)
MEASUREMENT
PRESSURE TEMPERATURE FLOW
ROTATING SHAFTS
UNIDIRECTIONAL BIDIRECTIONAL
PUSH - PULL LEVER PEDALGENERAL MANUAL PUSH BUTTON SPRING
FIXED
DISPLACEMENT
VARIABLE DISPLACEMENT
NON-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
BASIC
SYMBOL
SPRING
LOADED
CHECK VALVES
2 POSITION
INFINITE
POSITIONING
FLOW IN ONE
DIRECTION
FLOW IN
EITHER
DIRECTION
3 POSITION
CROSS
FLOW
PARALLEL
FLOW
INTERNAL PASSAGEWAYS
NORMAL POSITION
AB
PT
AB
PT
SHIFTED POSITION INFINITE POSITION
CONTROL VALVES
ATTACHMENT
MANUAL SHUTOFF
SHUTTLE PILOT
CONTROLLED
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 TRIANGLES
HYDRAULIC PNEUMATIC
INTERNAL
SUPPLY PRESSURE
COMPLETE
FIXED
DISPLACEMENT
VARIABLE DISPLACEMENT
NON-COMPENSATED
HYDRAULIC SYMBOLS (ELECTRICAL)
ELECTRICAL SYMBOLS TABLE
325-AG135 PK-14
HARNESS IDENTIFICATION CODE THIS EXAMPLE
INDICATES WIRE 135 IN HARNESS “AG”
325-PK-14
WIRE GAUGE
WIRE COLOR
CIRCUIT NUMBER
IDENTIFICATION
WIRE NUMBER IDENTIFICATION CODES
CURRENT STANDARD
PREVIOUS STANDARD
ELECTRICAL SCHEMATIC EXAMPLE HYDRAULIC SCHEMATIC EXAMPLE
325-PK
WIRE COLOR
CIRCUIT NUMBER
IDENTIFICATION
B
WIRE
WIRE
(EXAMPLE VALVE)
CURRENT STANDARD
TRANSDUCER
(FLUID)
M
ELECTRIC MOTORTRANSDUCER
(GAS / AIR)
G
GENERATOR
PRESSURE SWITCH ELECTRICAL WIREPRESSURE SWITCH
(ADJUSTABLE)
TEMPERATURE
SWITCH
PRESSURE
SWITCH
TEMPERATURE
SWITCH
LEVEL
SWITCH
FLOW
SWITCH
ELECTRICAL SYMBOLS (ELECTRICAL)
A
CIRCUIT NUMBER
IDENTIFICATION
WIRE
COLOR
WIRE GAUGE
T
KENR9016
24 Page, (Dimensions: 34 inches x 28 inches)
22
(A) Extendable Stick Control Valve
(B) Stick Control Valve
(C) Bucket Control Valve
(D) Swing Control Valve
(E) Boom Control Valve
(F) Auxiliary Control Valve
(G) Middle Inlet Manifold
(H) Left Stabilizer Control Valve
(J) Right Stabilizer Control Valve
(K) Solenoid for the Sideshift Lock
K
A
B
C
D
E
F
G
HJ
BACKHOE VALVE
IMPLEMENT / STEERING PUMP
A
A
T2
T2
T1
T2
SOS
T1
B
F
C
B
D
E
C
D
F
COMPONENT LOCATIONS
RIDE CONTROL
B
A
C
D
SOS
Implement and
Steering Pump
HYDRAULIC OIL FILTER
SOS
Pressure Switch
LOADER VALVE
E
D
C
B
A
19
17
15 16
15
2
2
16
19
17
10
10
6
6
6
14
14
14
7
7
7
98
9
8
11
3
3
11
4
4
1312
12
13
5
5
1
118
1821
21
20
20
22
Tap Description
T1 Pump Discharge
T2 Load Sense
SOS Oil Sampling
TAP LOCATIONS
NOTE: Alpha numeric numbers are represented by the number only on the machine views.
Hydraulic Oil Filter
Hydraulic Oil Filter
(A) Pressure Cutoff
(B) Flow Compensator
(C) Inlet Port
(D) Case Drain Port
(E) Hydraulic Oil Tank
(F) Outlet Port
(T1) Discharge Pressure Tap
(T2) Load Sensing Pressure Tap
(A) Ride Control Relay
(B) Ride Control Solenoids
(C) Ride Control Accumulator
(D) Ride Control Pressure Switch
BACKHOE VALVE
(A) Mechanically Controlled Loader Valve
(B) Inlet Manifold
(C) Lift Control Valve
(D) Tilt Control Valve
(E) Auxiliary Control Valve (OPT)
Description
Part
Number
Machine
Location
Schematic
Location
Accumulator - Ride Control 162-3960 1 C-7
2-B22022-412liO-relooC
Cylinder - Boom 210-7074 3 F-4
Cylinder - Bucket 210-7086 4 F-2
Cylinder - E-Stick 210-7098 5 F-1
Cylinder - Lift (ST) 215-7298 6 B-7
Cylinder - Lift (PL) 214-9373 6 B-7
Cylinder - MP Bucket 226-5540 7 A-7
Cylinder - Stabilizer (LH) 173-4565 8 F-6
Cylinder - Stabilizer (RH) 173-4565 9 F-7
Cylinder - Steer (Front) 214-5097 10 A-4
Cylinder - Stick 210-7080 11 F-2
Cylinder - Swing (LH) 228-3506 12 F-3
Cylinder - Swing (RH) 228-3507 12 F-3
Cylinder - Tilt (ST) 206-3553 13 B-7
Cylinder - Tilt (PL) 192-3884 13 B-7
1-C413426-012liO-retliF
Pump Gp - Metering 247-7868 15 B-4
Pump Gp - Piston 296-6714 16 B-2, B-3
Switch - Pressure (Ride Control) 304-5696 17 C-7
3-A817778-542pGknaT
Valve - Backhoe (SS) 7-Bank 248-0487 19 D-E-1:D-E-7
Valve - Backhoe (SS) Aux. - KIT 259-6733 19 D-4, E-4
Valve - Backhoe (SS) Boom 259-673
9 19 D-4, E-4
Valve - Backhoe (SS) Bucket 259-6737 19 D-3, E-3
Valve - Backhoe (SS) E-Stick 259-6734 19 D-1, E-1
Valve - Backhoe (SS) Inlet Manif. 259-6744 19 D-5, E-5
Valve - Backhoe (SS) Stabilizer 259-6746 19 D-6,7:E-6,7
Valve - Backhoe (SS) Stick 259-6735 19 D-2, E-2
Valve - Backhoe (SS) Swing 259-6738 19 D-3, E-3
Valve - Loader (PL) 3-Bank 247-9656 20 A-5,6:C-5,6
Valve - Loader (PL) Inlet 259-6743 20 C-5, C-6
Valve - Loader (PL) Tilt 259-6741 20 B-5,B-6
Valve - Loader (ST) 2-Bank 248-0481 20 A-5,6:C-5,6
Valve - Loader (ST) 3-Bank 248-0482 20 A-5,6:C-5,6
Valve - Loader (ST) Inlet 259-6745 20 C-5, C-6
Valve - Loader (ST) Lift 259-6732 20 B-5, B-6
Valve - Loader (ST) Tilt 2-Bank 259-6731 20 B-5, B-6
Valve - Loader (ST) Tilt 3-Bank 259-6730 20 B-5, B-6
Valve - Loader (ST) Aux. 259-6729 20 A-5, A-6
Valve - Ride Control 245-8780 17 C-7
Valve Asy - Shuttle 8J-6875 21 D-6,7:E-6,7
Valve Gp - Cushion (OPT) 320-7812 19 F-3
Component Locations
Hydraulic oil filter bypass switch is mounted
to oil filterbase
LINE PATTERNS
Drain / Return Lines
Component Group
Pilot / Load Sensing Pressure
Pressure Line
Attachment
Air Line
CALLOUTS
Taps (Pressure, Sampling, Sensor - by letter)
Components (By number)
YY
52
HYDRAULIC CIRCUIT COLOR DESCRIPTIONS
MAIN PUMP OUTPUT
LIFT CYLINDER CIRCUIT
BUCKET CYLINDER CIRCUIT
LOAD SENSE CIRCUIT
STEERING CIRCUIT
STICK CYLINDER CIRCUIT
SUPPLY LINE
BOOM CYLINDER CIRCUIT
TILT CYLINDER CIRCUIT
AUXILIARY CIRCUIT (LOADER VALVE)
DRAIN / RETURN LINE
STABILIZER CYLINDER CIRCUIT
SWING CYLINDER CIRCUIT
E-STICK CYLINDER CIRCUIT
AUXILIARY CIRCIUT
KENR9016
24 Page, (Dimensions: 34 inches x 28 inches)
THIS SCHEMATIC IS FOR THE 422E AND 428E BACKHOE LOADER
MEDIA NUMBER: RENR9016
PART NUMBER: 322-3113, CHANGE: 00, VERSION: S
Components are shown installed on a fully operable machine.
Refer to the appropriate Service Manual for Troubleshooting, Specifications.
A
B
C
D
E
F
1234567
A
B
C
D
E
F
1234567
PUMP GP
(METERING)
247-7868
PUMP GP
(PISTON)
296-6714
COOLER
214-2202
FILTER
210-6243
BUCKET
CYLINDER
226-5540
TILT
CYLINDER
LIFT
CYLINDER
206-3553(ST)
192-3884(PL)
RIDE CONTROL
ACCUMULATOR
162-3960
INLET MANIFOLD
259-6744
BOOM CYLINDER
210-7074
SWING CYLINDER-RH
228-3507
SWING CYLINDER-LH
228-3506
BUCKET CYLINDER
210-7086
STICK CYLINDER
210-7080
E-STICK CYLINDER
210-7098
STABILIZER CYLINDER-LH
173-4565
STABILIZER CYLINDER-RH
173-4565
LOADER VALVE
248-0481 2-BANK (ST)
248-0482 3-BANK (ST)
247-9656 3-BANK (PL)
LIFT
VALVE
259-6732
TILT
VALVE
AUX. VALVE
259-6729
LOADER INLET
259-6745(ST)
259-6743(PL)
VALVE ASY.
(SHUTTLE)
8J-6875
FRONT
STEER
CYLINDER
214-5097
STABILIZER VALVE-RH
259-6746
STABILIZER VALVE-LH
259-6746
KIT AUX. VALVE (OPT)
259-6733
BOOM VALVE
259-6739
SWING VALVE
259-6738
BUCKET VALVE
259-6737
STICK VALVE
(7 BANK)
259-6735
E-STICK VALVE
259-6734
TANK GP
245-8777
RIDE CONTROL VALVE
245-8780
PRESSURE
SWITCH
304-5696
BACKHOE VALVE
7 BANK
248-0487
LOADER VALVE
VALVE GP
CUSHION
(OPT)
320-7812
SIDESHIFT
SOS
T2
T1
192-3884(PL)
206-3553(ST)
TILT
(ST) 2-BANK
259-6731
(ST) 3-BANK
259-6730
(PL) 3-BANK
259-6741
