H-20 The Bucket Moves Slowly Or The Tilting-Back Force Is Insufficient - Komatsu WA250-6 Shop Manual

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

H-20 The bucket moves slowly or the tilting-back force is insufficient

H-20 The bucket moves slowly or the tilting-back force is insufficient
Inspection before diagnosis
Is the stroke of the bucket control lever
q
appropriate?
Seizure of work equipment linkage
q
bushing (Does any abnormal noise
occur?)
Check of abnormality
Make sure in an actual operation that
q
the tilting-back force is insufficient.
Measure the operating speed of the
q
bucket, and make sure referring to the
criterion value table that the speed is
abnormal
No.
Diagnosis
The lift arm rising force and speed are
1 abnormal, and the bucket tilting force and
speed are abnormal
The lift arm rising force and speed are nor-
2 mal, and the bucket tilting force and speed
are abnormal
When the oil temperature rises in item 1, the
3
bucket speed becomes worse
The hydraulic pump is causing an abnormal
4
noise
5 Large hydraulic drift of bucket cylinder
The relief oil pressure from the relief valve of
6
the work equipment valves is low
The relief oil pressure from the relief valve of
7
the work 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
Q
Cause
HST PPC
Work equipment valve Cylinder
pump valve
d e f
E E
A
X X X
Q Q
Q
Q
Q
SEN03849-00
1
g h i
E
X X X
Q Q Q
Q
Q Q Q
Q
23
40-500