Komatsu WA250-6 Shop Manual

SEN03849-00
40-500 16 WA250, 250PZ-6
500 Troubleshooting of hydraulic and mechanical system (H-mode)
H-10 The brake does not work or does not work well
H-10 The brake does not work or does not work well 1
Ask the operator about the following:
q Has the brake come not to work suddenly?
o Breakage of brake equipment
q Has the brake come not to work gradually?
o Wear of lining and disc, defective seal
Inspection before diagnosis
q Is the oil level in the hydraulic tank appropriate?
q Is the play of brake pedal appropriate?
q Oil leak from brake tube and connector, deformation of
tube.
q Tire air pressure and state of tire tread.
Check abnormality
q Measure the braking force and check referring to the stan-
dard value table if the brake does not work practically.
Cause
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Defective brake piston seal in axle Defective operation of brake piston in axle Defective slack adjuster Wear or abnormality of brake lining in axle Metal contact due to complete wear of brake lining in axle Mixing of air in brake circuit Defect inside brake valve Defective seal of accumulator piston, insufficient gas pressure Defective operation of accumulator charge valve Defective brake pump (For charge) Defective brake linkage
No.
Remedy
Diagnosis
E
X
E
XX
E
X
E
X
E
X
E
XX
E
XA
1 When the brake pedal is stepped on, only a little resistance is felt
QQQQQ
2 When the brake pedal is stepped on, a strong resistance is felt
QQ
3
When the brake works, an abnormal noise occurs from the axle
brake
QQ
4
When the four wheels are jacked up, the axle is placed on a table
and the brake is applied at the first forward speed, only a specific
wheel rotates
QQ QQ
5
An airflow is observed in bleeding air from brake circuit, and the
brake returns to normal after the bleeding
Q
6 Brake oil leaks abnormally from the axle during inspection
Q
7 Much metal powders are mixed in the axle oil
Q
8
The brake pedal leg-power and stroke are normal, but the brake
does not work well
QQQQQQQQQ
9 The brake does not work often when the engine is stopped
Q Q QQQQ
10 The accumulator is not charged, and a buzzer sounds
QQQ
11 The brake works after some time lag
QQQ

Komatsu WA250-6 Specifications

General

Brand	Komatsu
Model	WA250-6
Category	Compact Loader
Language	English