©
2003 Caterpillar
All Rights Reserved
Printed in U.S.A.
RENR2909
July 2003
345B Series II Excavators
Medium Pressure
CCC1-UP
FEE1-UP
DET1-UP
Hydraulic System (Attachment)
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
PEDAL
GENERAL 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
BA
DR1
MU
PG1
MU
DR2
AB
PG2PG3
JR1
JR3
JR4
JR2
JRT
JRP
JL2
JL4
JL1
JL3
JLT
JLP
AR1
BR1
AL2BL2
X
DR
HL
dL5
aL5
BL4
bL4
AL3
BL3
aL3
bL2
AL1
BL1
aL1
PSW
aR1
aR2
AR2
BR2
bR3
aR4
Y
HR
AR4
R1
dSW
bR2bR1
PL
PR
Pp1
bL1
PAT
aL2 bL3
aL4
PiL
aR3dR4
SA5
SA4
SA3
SA2
SA1
SB5
SB4
SB3
SB2
SB1
SP
dR5
AR3
BR3
R2
R3
APi2
PP2
TT
TP
TLA1
TLA2
TRA2
TRA1
PSL
APi
ADr
AL4
B
L
L1
S
X
T1
L'
L'
B' A'
BR
BR
MB
MA
MB
A'B'
T1
A'B'
B
A
T2
X
T2
MA
B
A
X
PTA
P
T
LS
M
B
A
Pi8
PSA
PG
TOUT
DR1DR2DR3
DR4
DR5
DR6
Pi3
PIN
PEU
Pi1
Pi2
C/V
JPi
Pi5
PAC
C
Pi3
)(
T
Pi1
Pi2
Dr1
OWD
X1X2
Dr2
Bd1
Bd2
A
B
C
T
Pi
A
Dr
X
A
Pi
)(
)(
)(
)(
Dr
X
C
B
A
Dr
Pi
P2
P1
P1
P2
Dr
A2
A1
R1
S
R2
X1
X2
M3
X3
A1
M1
A2
M2
R1
A3
S2
1
1
Item
No.
Description
ATTACHMENT COMPONENTS
Auxiliary Control Valve
1
This Attachment Schematic is intended to
be used in conjunction with the Standard
Hydraulic Schematic in this Service Manual.
Hydraulic Schematic
211-7318
PILOT LINE
DRAIN LINE
MAIN CONNECTOR LINE
