©
2003 Caterpillar
All Rights Reserved
Printed in U.S.A.
RENR5406-02
February 2003
385B Excavator
Hydraulic System
MYA1-UP
BKF1-UP
ANS1-UP
BKX1-UP
BLY1-UP
RCD1-UP
PIN
Pi3
Pi2
Pi1
Pi6
Pi5
DR6
DR5
DR4
PAC
PSA3
PSA2
PSA1
PSA4
DR3
DR2
DR1
TOUT
PG
13
14
50
15
51
49
17
43
58
18
19
20
36
44
88
55
60
59
57
54
56
42
29
87
41
39
48
47
46
86
45
22
21
37
67
63
62
61
16
Main Control Valve
Pilot Oil Manifold
65
C
PR
PB
E
F
SWING
PR
A
Dr
B
Dr
Pi
Pi
Pa
Pb
D
LEFT
D
F
E
FWD FWD
TRACK
aL4
bR1
bL1
R2
A
B
TRAVEL
(L)
TRAVEL
(R)
Pa
Dr
C
FRONT
P
T
M2
M1
REAR
B
A
N
IN
L2
L1
Qmax Qmin
REV
M1
T2T1
R
S
A
M
G
aL1
BL1
AL1
LS2
B
L1
L
S
REV
aR1
bL4
D1
D2
AL4
BR1
AR1
PSga2a1
BL4
PF
PS1
STICK
LS1
SA1
P2
P1
)(
P1
P2
Dr
B1
SA2
OUT
RIGHT
P1
P2
Dr
BL2
AL2
PSA3
PSA2
PSA1
PG
PIN
TOUT
DR1
DR2
DR3
Pi5
PAC
Pi3
Pi2
Pi1
Pi4
Pi6
PSA4
DR6
aR3
aL3
bR3
bL3
ATT
AR3
BR3
AL3
BL3
DR5
bL2
PR
B
A
aL2
R1
BUCKET
UP
BOOM
DR4
Pb
Pi
Pi
)(
B
Dr
A
CLOSE
PR
DOWN
OPEN
N
P
PILOT LINE
DRAIN LINE
Hydraulic Schematic
158-8129
Item
Component
STANDARD COMPONENTS
Component
No.
Item
No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
27
26
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
88
87
86
85
84
83
82
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
81
80
Bucket Cylinder
Stick Cylinder
Boom Cylinders
Right Travel Motor
Left Travel Motor
Front Swing Motor
Swing Parking Brake Solenoid Valve
Rear Swing Motor
Travel Brake Valve (Right)
Travel Brake Valve (Left)
Swivel
Swing Control Valve
Proportional Valve (Attachment Spool)
Proportional Valve (Bucket Cylinder Rod End)
Proportional Valve (Boom Cylinder Rod End)
Main Control Valve
Signal Duplication Valve
Proportional Valve (Stick Cylinder Rod End)
Proportional Valve (Left Travel) (Forward)
Proportional Valve (Right Travel) (Forward)
Solenoid Valve (Neutral Bypass)
Differential Pressure Relief Valve (Rear Pump)
Attachment Control Valve
Flow Compensator Valve (Bucket)
Bucket Control Valve
Flow Compensator Valve (Boom)
Load Check Valve
Boom Control Valve
Signal Relief Valve (High Pressure)
Stick Control Valve
Flow Compensator Valve (Stick)
Left Travel Control Valve
Flow Compensator Valve (Left Travel)
Right Travel Control Valve
Flow Compensator Valve (Right Travel)
Defferential Pressure Relief Valve (Front Pump)
Neutral Flow Control Valve
Flow Compensator Valve (Attachment)
Line Relief Valve (Bucket Cylinder Rod End)
Line Relief Valve (Bucket Cylinder Head End)
Line Relief Valve (Boom Cylinder Rod End)
Signal Relief Valve (Low Pressure)
Return Port
Return Port
Solenoid Valve (High/Low Relief) Travel/Stick
Proportional Valve (Attachment Spool)
Proportional Valve (Bucket Cylinder Head End)
Proportional Valve (Boom Cylinder Head End)
Line Relief Valve (Boom Cylinder Head End)
Solenoid Valve (Boom Drift Reduction Valve)
Boom Drift Reduction Valve
Inlet Port (Front Pump Flow)
Inlet Port (Rear Pump Flow)
Stick Drift Reduction Valve
Solenoid Valve (Stick Drift Reduction Valve)
Line Relief Valve (Stick Cylinder Rod End)
Proportional Valve (Stick Cylinder Head End)
Line Relief Valve (Stick Cylinder Head End)
Proportional Valve (Left Travel) (Reverse)
Proportional Valve (Right Travel) (Reverse)
Travel Speed Solenoid Valve
Pilot Relief Valve
Valve
Pilot Oil Manifold
Accumulator
Solenoid Valve (Hydraulic Activation)
Pilot Filter
Bypass Check Valve
Back Pressure Valve
Radiator Fan Motor
Oil Cooler Fan Motor
Front Pump Pressure Sensor
Swing Pump Pressure Sensor
Drain Filter
Return Filter
Hydraulic Tank
Return Filter
Drain Filter
Front Pump
Charge Pump
Rear Pump
Pilot Pump
Cooling Pump
Swing Pump
Main Control Valve Body (Boom Side)
Center Manifold
Main Control Valve Body (Stick Side)
1
2
3
3
4
9
5
10
11
6
7 8
12
13
14
15
16
21
22
23
24
25
26
27
28
45
37
38
46
39
41
48
49
50
51
52
53
42
43
29
17
47
40
55
54
56
19 2018
30
31
32
33
34
35
36
44
60
59
57
58
61
62
63
64
65
66
67
68
69
70
75
76
78
71
72
79
77
80
81
82
73
83
84
85
74
P
Proportional Reducing Valve (PS Pressure)
2
1
3
6
72
71
11
7 8 12
82
4 9
81
80
5 10
83 84 85
MAIN CONNECTOR LINE
g00975646
