Operation & Maintenance Manual
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LG958L/LG959 Wheel Loader
98
3.8.4 Hydraulic System of Work Equipment
No.
Problems
Possible Causes
Remedy
1
1
Insufficient
rising force of
life-arms
1
Over worn or damaged cylinders
2
Over worn multi passage valve,
excessive clearance between valve
spool and valve block
3
Oil leakage of oil lines
4
Severe internal leakage of working
pump
5
Idle suction of working pump
6
Low set pressure value of safety valves
7
Clogged suction tube and filter
1
Change the oil seals of cylinder
2
Change the distribution valve
3
Find out the leaking points and
repair
4
Change the oil pump
5
Check oil lines and remedy
6
Regulate the system pressure to
set value
7
Clean the filter, strainer, and
change oil
2
Insufficient force
of the bucket, the
bucket tend to
lower down or
float up
1
Damaged seal ring of steering cylinder
piston
2
Over worn of multi passage valve,
excessive clearance between valve
spool and valve block
3
Low set pressure value of safety valves
4
Overload valve and oil complementary
valve is blocked by dirt
1
Change the oil seals
2
Change multi passage valve
3
Change the system pressure to
its prescriptive value
4
Disassemble and clean
3
Hydraulic oil
mixing into
gearbox
Aged or broken oil seals of working pump
or steering pump lead to the hydraulic oil
leaking into the gearbox
Change oil seals or change oil
pump
4
Foam in hydraulic
oil tank and harsh
noise
1
Suction oil line is damaged and air is
sucked into oil lines
2
Low oil level and large amount of air is
sucked into oil lines
1
Check the oil lines, remedy the
leaking parts. Replace if
necessary.
2
Add hydraulic oil to specified
level
