Komatsu Galeo PC138US-8, Shop Manual, Page: 447 / 946

30 Testing and adjusting SEN02460-01
PC138US, USLC-8
11
4. Hydraulic circuit
* Gauge changing work: Change hoses of gauges [3] and [4].
No. Checked part
Checking condition
[1] [2] [3] [4] [5]
G
ood
Ba
d
600K 600K 600K 600K 60K
Fuel
control
dial
Work-
ing
mode
Operation of work equipment
Pump
main 1
Pump
main 2
Pump
LS 1
Pump
LS 2
Control
1
Self pressure
reducing valve
MAX P
All lever in neutral — — — —
A
2 Main relief valve Arm out relief
B B
— — —
3 Unload valve All levers in neutral
C1 C1 C2 C2
—
4 LS valve
Right track driven idle
Lever moved halfway
D1
—
D2
— —
Left track driven idle
Lever moved halfway
—
D1
—
D2
—
5
Swing motor
safety valve
Swing lock
Right swing relief
E E
— — —
Swing lock
Left swing relief
E E
— — —
6
Main relief valve
Travel motor
Safety valve
Travel junction
valve
Right travel lock
Right forward relief
F
— — — —
Right travel lock
Right reverse relief
F
— — — —
Left travel lock
Left forward relief
—
F
— — —
Left travel lock
Left reverse relief
—
F
— — —
S
tandard value
Checked oil pressure Unit Standard value for new machine Service limit value
A (Control circuit basic pressure)
MPa
{kg/cm
2
}
3.0 – 3.4 {31 – 35} 2.7 – 3.7 {28 – 35}
B (Work equipment relief pressure) 33.8 – 35.8 {345 – 365} 33.8 – 36.8 {345 – 375}
C (Unload pressure) 1.8 – 3.8 {18 – 38} 1.8 – 3.8 {18 – 38}
D (LS differential pressure) 2.1 – 2.3 {21.5 – 23.5} 2.1 – 2.3 {21.5 – 23.5}
E (Swing relief pressure) 28.2 – 30.2 {288 – 308} 26.7 – 30.7 {273 – 313}
F (Travel relief pressure) 33.8 – 35.8 {345 – 365} 32.8 – 36.8 {335 – 375}
No. Check item
Checking condition
[1] [2] [3a] [4a] [5]
Go
o
d
Bad
600K 600K 600K 600K 60K
Fuel
control
dial
Work-
ing
mode
Operation of work equipment
F pump
main
R pump
main
F pump
servo
R pump
servo
Control
7 Servo piston MAX P Arm out relief
H1 H1 H2 H2
—
S
ta
nda
rd v
a
lu
e
Checked oil pressure Unit Standard value for new machine Service limit value
H (Servo control pressure) —
H1 : H2 = 1 : 0.6
(Oil pressure ratio)