H-13 The Lift Arm Moves Slowly Or The Lift Arm Rising Force Is Insufficient - Komatsu WA250-6 Shop Manual

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

H-13 The lift arm moves slowly or the lift arm rising force is insufficient

H-13 The lift arm moves slowly or the lift arm rising force is insufficient
Inspection before diagnosis
Is the stroke of the lift arm control lever appropri-
q
ate?
Check of abnormality
Rising force and speed problem are closely
q
related, and this problem occurs as insufficient ris-
ing speed at first. Measure the lift arm rising speed
when the lift arm is loaded and make sure referring
to the criterion table that the speed is abnormal.
No.
Diagnosis
The bucket tilting force and speed are abnormal, and
1
the lift arm rising speed is slow
The bucket tilting force and speed are normal, and the
2
lift arm rising speed is slow
When the oil temperature rises in item 1, the lift arm
3
speed becomes very slow
4 The hydraulic pump causes an abnormal noise
5 Large hydraulic drift of lift arm cylinder
The relief oil pressure from the relief valve of the work
6
equipment valves is low
The relief oil pressure from the relief valve of the work
7
equipment valves is too high
WA250, 250PZ-6
Tank to Priority
Pump valve
a b c
E E
C
Remedy
E X X
Q Q Q
Q
Q Q
SEN03849-00
Cause
HST PPC Work equipment
pump valve valve
d e f
E E
A
X X X
Q Q
Q
Q
Q
1
Cylinder
g h
E
X X
Q Q
Q
Q Q
19
40-500