Sakai SW800 Series, Shop Manual

Page: 154 / 159

4-411
Fault Finding for Hydraulic and Mechanical Systems
b) Speed not gained or low traction in either forward or backward travel direction.
4
Does unloader
valve stay closed?
3
5
YES
NO
Does machine travel at
same speed forward
and backward at medi-
um engine speed with
front motor ports A and
B (motor side and
pump side) blocked ?
Is faulty condition
reversed if front
high pressure relief
valve is exchanged
with rear one?
Does machine travel at
same speed forward and
backward at medium
engine speed with rear
motor ports A and B (mo-
tor side and pump side)
blocked ?
1
2
YES
NO
YES
NO
Does F-R lever
move correctly?
Is there any dif-
ference in charge
reassure between
forward travel and
backing?
YES
YES
NO
NO
7
NO
YES
Are pump servo
valve and servo
linkage normal?
YES
NO
6
A
B
Possible cause
Remedy
To ‘A’ on this page
Pump servo valve or servo
linkage defective.
Repair. Renew
if necessary.
F-R lever linkage faulty.
Unloader valve lever position
incorrect.
Set correctly.
Leakage at pump servo
device.
To ‘B’ on this page
Rear wheel drive motor
faulty
Propulsion pump faulty.
Front wheel drive motor faulty.
Repair. Renew
if necessary.
Repair. Renew
if necessary.
High pressure relief valve
faulty.
Clean and adjust.
Renew if
necessary.
Repair. Renew
if necessary.
Repair. Renew
if necessary.
Repair. Renew
if necessary.