Machine Does Not Travel Straight - Komatsu PC200-8M0 Shop Manual

500 Troubleshooting of hydraulic and mechanical system (H-mode)
H-17 Machine does not travel straight
H-17 Machine does not travel straight
q
Failure

Machine does not travel straight

Related infor-
q
Perform all troubleshooting with working mode in power mode (P).
mation
Malfunction of travel PPC
1
valve
Malfunction of self-pressure
2
reducing valve
Defective adjustment or mal-
3
function of LS valve
Probable
causes and cri-
teria
Malfunction of travel junc-
4
tion solenoid valve
Malfunction of travel junc-
5
tion valve
Malfunction of travel control
6
valve (spool)
7 Defective travel motor
8 Defective final drive
PC200, 200LC, 220, 220LC-8M0
Cause
a Be ready with engine stopped, then troubleshoot with engine
high idle.
a Be ready with engine stopped, then troubleshoot with engine
high idle.
All levers in the neutral position
a Be ready with engine stopped, then troubleshoot with engine
high idle.
Measured oil pres-
Pump discharge
PC valve output pres-
If normal oil pressure is not obtained by adjustment, the LS valve
may malfunction or have internal defect. Check LS valve.
a Be ready with engine stopped, then troubleshoot with engine
high idle.
Both sides in the NEUTRAL
Travel junction valve may malfunction. Check it.
Spool of travel control valve may malfunction. Check it.
a Be ready with engine stopped, then troubleshoot with engine
high idle.
Final drive may have internal defect. Check it.
* It may be checked by abnormal sound, abnormal heating,metal
chips in drain oil, etc.
Criteria and troubleshooting procedure
Travel lever
Neutral
Forward
Reverse
Control lever
Operation of levers and oil pressure ratio
All levers in the neu-
sure
tral position
pressure Almost same pres-
sure
sure
Travel lever
position
Either side operated
Travel lever
Travel system relief
SEN06139-00
PPC valve output pressure
0 MPa
2
{0 kg/cm }
2.84 to 3.43 MPa
2
{29 to 35 kg/cm }
Control circuit source pressure
2.84 to 3.43 MPa
2
{29 to 35 kg/cm }
Run the track off
ground.
(lever at half stroke)
1
Approx. 0.6 (Approx.
3/5)
Travel junction solenoid valve
output pressure
0 MPa
2
{0 kg/cm }
Approx. 2.9 MPa
2
{Approx. 30 kg/cm }
Leakage from travel motor
27.2 l/min
40-500
27