H-5 Fine Control Performance Or Response Is Poor - Komatsu PC88MR-10 Shop Manual

40 Troubleshooting
Troubleshooting of hydraulic and mechanical system (H-
mode)

H-5 Fine control performance or response is poor

Fine control performance or response is poor.
Failure
Related
Perform all troubleshooting with working mode set in power (P) mode.
information
No. Cause
Clogged orifice in LS
1
circuit
Defective adjustment of
2
LS valve
3 Malfunction of LS valve
Malfunction of servo
4
piston
40-470
Procedure, measuring location, criteria, and remarks
Orifice may be clogged. Check it.
a Be ready with engine stopped, then perform troubleshooting with engine at
high idle.
Lever position and oil pressure
Oil pressure to be
measured
Pump discharge Almost same as LS valve output
pressure
LS valve output Almost same as pump discharge
pressure
When pressure cannot be adjusted to normal level, check LS valve for
malfunction (fatigue of spring) or internal defect (stuck or seized LS spool).
Check orifices and filters in pump servo devices for clogging.
(PC88MR-FTB-400-A-Z0-A)
ratio
All levers in NEUTRAL
pressure
pressure
LS differential
pressure
Bucket CURL relief
Approx. 2.11 MPa
{21.5 kg/cm 2 }
PC88MR-10