In Combined Operation Of Swing And Boom Raise, Boom Rising Speed Is Low - Komatsu PC88MR-10 Shop Manual

40 Troubleshooting
Troubleshooting of hydraulic and mechanical system (H-
mode)
H-18 In combined operation of swing and boom RAISE, boom rising
speed is low
(PC88MR-D35-400-A-Z0-A)
In combined operations of swing and boom RAISE, boom rising speed is low.
Failure
If boom raise single operation is also slow, troubleshoot the following first.
Related
information
H-6 Boom speed or power is low
No. Cause
Malfunction of boom
1
raise assist valve
40-490
Procedure, measuring location, criteria, and remarks
a Release remaining pressure from hydraulic tank and piping, and then
perform troubleshooting with engine stopped.
Check for stuck or seized spool in control valve body.
(It must be moved smoothly and must not be caught.)
Check if the check valve in the spool is not caught in the middle. Remove
it from spool and check if the check valve is not stained or damaged.
Check spring of check valve for fatigue and deformation.
PC88MR-10