SENR8919
16 Page
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)
2-SECTION PUMP
MAIN
AUX.
SPRING
(ADJUSTABLE)
VARIABILITY
LINE RESTRICTION
(VARIABLE)
LINE RESTRICTION
VARIABLE and PRESSURE
COMPENSATED
PRESSURE
COMPENSATION
PUMP: VARIABLE and
PRESSURE COMPENSATED
ENERGY TRIANGLES
HYDRAULIC PNEUMATIC
MEASUREMENT
PRESSURE
TEMPERATURE
FLOW
ROTATING SHAFTS
UNIDIRECTIONAL BIDIRECTIONAL
PUSH-PULL LEVER PEDALGENERAL MANUAL PUSH BUTTON SPRING
MANUAL CONTROL SYMBOLS
HYDRAULIC MOTORS
FIXED
DISPLACEMENT
VARIABLE DISPLACEMENT
NON-COMPENSATED
UNIDIRECTIONAL
BIDIRECTIONAL
HYDRAULIC PUMPS
FLUID STORAGE RESERVOIRS
CROSSING AND JOINING LINES
VALVE ENVELOPES
VALVE PORTS
BASIC COMPONENT SYMBOLS
FLUID CONDITIONER
PUMP or MOTOR
FLUID POWER SYMBOLS
FIXED
DISPLACEMENT
VARIABLE DISPLACEMENT
NON-COMPENSATED
UNIDIRECTIONAL
BIDIRECTIONAL
VALVES
PILOT CONTROL SYMBOLS
RELEASED PRESSURE
EXTERNAL RETURN
INTERNAL RETURN
REMOTE SUPPLY PRESSURE
SIMPLIFIED
COMPLETE
INTERNAL
SUPPLY PRESSURE
ACCUMULATORS
SPRING LOADED
GAS CHARGED
SOLENOID
or MANUAL
SOLENOID
and PILOT
SOLENOID and
PILOT or MANUAL
COMBINATION CONTROLS
SOLENOID
SERVO
THERMAL
DETENT
HYDRAULIC AND PNEUMATIC CYLINDERS
DOUBLE ACTING
SINGLE ACTING
BASIC
SYMBOL
SPRING
LOADED
CHECK VALVES
TWO
POSITION
INFINITE
POSITIONING
FLOW IN ONE
DIRECTION
FLOW ALLOWED IN
EITHER DIRECTION
THREE
POSITION
CROSS
FLOW
PARALLEL
FLOW
INTERNAL PASSAGEWAYS
NORMAL POSITION
A B
P T
A B
P T
SHIFTED POSITION
INFINITE POSITION
CONTROL VALVES
ATTACHMENT
MANUAL SHUTOFF
SHUTTLE PILOT
CONTROLLED
Hydraulic Symbols (Electrical)
Electrical Symbols Table
325-AG135 PK-14
Circuit Identification
Number
Wire Color
Wire Gauge
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
A
Wire
Wire
(EXAMPLE VALVE)
Current Standard
Transducer
(Fluid)
Transducer
(Gas / Air)
G
Generator
Electrical Wire
Pressure Switch
M
Electric Motor
Pressure Switch
(Adjustable)
Temperature Switch
T
Pressure
Symbol
Temperature
Symbol
Level
Symbol
Flow
Symbol
Electrical Symbols (Electrical)
Common Action
SENR8919
September 1995
350 & 350 L Excavators
Hydraulic System - Attachment
350:
2ZL171-UP
350 L:
3ML685-UP
9FL420-UP
©
1995 Caterpillar
All Rights Reserved
Printed in U.S.A.
RENRNNNN-NN VOL 1
NN Page, Color 2, EAR
THIS HYDRAULIC SCHEMATIC IS FOR THE 350 and 350 L EXCAVATOR
PART #: 113-6529 (COMMON ACTION ATTACHMENT)
Components are shown installed on a fully operable machine with the key and engine
off and transmission shifter in neutral.
Refer to the appropriate Service Manual for Troubleshooting, Specifications and Systems Operations
1
Item No. Description
1 Ball Valve
2 Relief Valve
3 Pilot Valve (Foot Operated)
ATTACHMENT COMPONENTS
XA
XB
MA
PD
JL3
JL1
JR3
JR1
JR2
(REV)
(FWD)
TRT
TLP
TLA1
TLA2
MA
G
A
ST2
SWING PUMP
TRA2
TRA1
(FWD)
(REV)
TRP
TLT
(CLOSE)
PUMP CONTROL
PRESS. SWITCH
SOLENOID VALVE
ON : H MODE
OFF : L,SMODE
PUMP CONTROL
PRESS.SWITCH
Pi
R
M
STICK CYLINDER
FRONT
BOOM CYLINDERBUCKET CYLINDER
PR
PG
E
F
SWING
D
SH SH
D
F
E
P
T
M2
M1
P1
T
P2
Pi
Dr
REV
FWD FWD
REV
A2
DR5
JPd
Jd
JPg
JP1
(OPEN)
(UP)
JL2JL4JR4
Pi1 Pi2 Pi3
aR3
DR1
aL3
bR3
DR2
DR3
bL3
aL1
aR1
bL4
aL4
bR1
PF
PR
bL1
TOUT
PIN
PG
DR4
AL4
BR1
R2
ATT
AR1
Pi4
BL1
AL1
IMP2
PSW
PTA
TRBM1
AR3BR3
AL3
BL3
AL2
PG
PR
FRONT
BL4
bL2
A3
A4
A5
A1
S
P
B1
T
B2
B3
BM2
IMP1
T
T
P
SD1
P
aL2
R1
STICK
A
BUCKET
CLOSE
BOOM
TRAVEL(L)
TRAVEL(R)
B4
B5
Z
Y
(DOWN)(CLOSE)
(OPEN)
STICKSWING
BOOMBUCKET
TRAVEL(R)
TRAVEL(L)
M
Pi2
Pi1
T
CLOSE
PD
P1
T
P2Pi
Dr
P
(REAR)
(FRONT)
PS1
LS1
S1Dr1 Dr2
LS2
OPEN
OPEN
BL2
PS
SA2
M2
P2
P1
M1
UPDOWN
TRAVEL ALARM
PRESS. S/W
SA1
ENGINE SPEED
SIGNAL
DOWN
UP
DS
dR1 HL1
SWIVEL
T1
RIGHT
L'
L'
B' A'
BR
BR
MB
MA
MB
A'B'
T1
LEFT
A'B'
B A
TRACK
T2
X
T2
LS
MA
B
A
DOUBLE
SINGLE
X
SWING 2 STEP
POWER CONTROL
MAIN CONNECTOR LINE
PILOT LINE
DRAIN LINE
1
2
3
D29542
3
12
