Komatsu PC200-8M0, Shop Manual

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SEN06139-00
PC200, 200LC, 220, 220LC-8M0 40-500
29
500 Troubleshooting of hydraulic and mechanical system (H-mode)
H-19 Machine is hard to steer or travel power is low
H-19 Machine is hard to steer or travel power is low
Failure
q
Machine is hard to steer or travel power is low
Related infor-
mation
q
Perform all troubleshooting with working mode in power mode (P).
Probable
causes and cri-
teria
Cause Criteria and troubleshooting procedure
1
Malfunction of travel PPC
valve (steering spool)
a
Be ready with engine stopped, then troubleshoot with engine
high idle.
Travel lever
PPC valve output pressure
(Steering)
Both sides in the NEUTRAL
position
0 MPa
{0 kg/cm
2
}
Either side operated
2.84 to 3.43 MPa
{29 to 35 kg/cm
2
}
2
Malfunction of travel junc-
tion solenoid valve
a
Be ready with engine stopped, then troubleshoot with engine
high idle.
Travel lever
Travel junction solenoid valve
output pressure
Both sides in the NEUTRAL
position
0 MPa
{0 kg/cm
2
}
Either side operated
Approx. 2.9 MPa
{Approx. 30 kg/cm
2
}
3
Malfunction of travel junc-
tion valve
Travel junction valve may malfunction. Check it.
4
Malfunction of merge-divider
main EPC valve
Merge-divider main EPC valve may malfunction. Check it.
5
Malfunction of merge-divider
LS-EPC valve
Merge-divider LS-EPC valve may malfunction. Check it.
6
Malfunction of merge-divider
main valve
Merge-divider main valve may malfunction. Check it.
7
Malfunction of merge-divider
LS valve
Merge-divider LS valve may malfunction. Check it.
8
Malfunction of travel control
valve (spool)
Spool of travel control valve may malfunction. Check it.
9
Malfunction of travel control
valve (pressure compensa-
tion valve)
Pressure compensation valve of travel control valve may malfunc-
tion. Check it.
10
Malfunction of travel control
valve (suction valve)
Suction valve of travel control valve may malfunction. Check it.
11
Malfunction of bucket control
valve (LS shuttle valve)
LS shuttle valve of bucket control valve may malfunction. Check it.
12
Defective seal of check valve
of LS pressure sensing part
(control valve side)
Seal of check valve of LS pressure sensing part (control valve
side) may be defective. Check it.
13
Defective seal of travel
motor (safety valve)
Seal of safety valve of travel motor may malfunction. Check it.
* Judgment can be made by checking a change of phenomenon
after exchanging safety valves between forward and reverse
circuit of the same motor or between right and left motor cir-
cuits.
14
Defective seal of travel
motor (check valve)
Seal of check valve of travel motor may malfunction. Check it.
* You may replace the check valves of forward and reverse sec-
tions of the same motor or those of the right and left motors
with each other and judge from the change of the phenomenon.