Komatsu PC88MR-10 Shop Manual page 961

No. Cause
12 Defective boom cylinder
PC88MR-10
Troubleshooting of hydraulic and mechanical system (H-
Procedure, measuring location, criteria, and remarks
Check that check valve is seated on valve body in position (it is not stuck
halfway).
a When disassembling the safety valve, replace the safety valve assembly
with a new one since its relief pressure cannot be adjusted on the
machine.
a Be ready with engine stopped, then perform troubleshooting with engine at
high idle.
Leakage from boom
cylinder
Boom RAISE hydraulic relief
40 Troubleshooting
mode)
Max. 7.5 cc/min
40-473