LG956 Wheel Loader. Instruction - page 25
Operation & Maintenance Manual──LG956L Wheel Loader
99
3.8 General Problems/Possible Cause/Remedies
3.8.1 Electrical System
No. Problems
Possible
Causes
Remedy
1
Lamp is not bright when the engine
runs at high speed.
2
Lamp flickers when the engine is
running.
1 Faulty cable ( contact
problem or open
circuit)
2 Improper adjustment
of fan belt tension
1. Check, and repair the loose
terminals and disconnections.
2. Refer to the “Operation and
Maintenance Manual” of diesel
engine to adjust the tension of fan
belt.
3
A meter does not work when
engine is running.
1 Faulty alternator
2 Faulty cable
3 Improper adjustment
of belt tension
1. Replace
2. Check and repair
3. Refer to “Operation and
Maintenance Manual” of diesel
engine for adjusting the tension of
fan belt.
4
Abnormal noise from alternator.
Faulty alternator
Replace
5
Do not start when starting switch is
turned on
1 Faulty cable
2 Insufficient battery
charge
1. Check and repair
2. Charge
6
Pinion of starting motor does not
mesh or keep meshing without
rotation.
Faulty battery charge
Charge
7
Starting motor turns feebly
1 Insufficient battery
charge
2 Faulty alternator
1. Charge
2. Replace
8
Starting motor disengages before
engine starts
1 Faulty cable
2 Insufficient battery
charge
1. Check and repair
2. Charge
Operation & Maintenance Manual──LG956L Wheel Loader
100
3.8.2 Transmission System
No. Problems
Possible
Causes
Remedy
1
Shifting
pressure of
every gear is
low
1 Low oil level in gearbox oil sump
2 Oil leakage in the main oil lines
3 Clogged oil filter of gearbox
4 Faulty converter charging pump
5 Improper adjustment of the
pressure-regulator valve in transmission
control valve
6 Invalid spring of pressure-regulator
valve in transmission control valve
7 Pressure-regulator valve of
transmission control valve or
accumulator piston is locked
1 Add oil to the specified level
2 Check the main oil lines
3 Clean or replace the filter
4 Disassemble and check the converter
charging pump or replace it
5 Readjust to the specified value
6 Change the spring of pressure
regulator valve
7 Disassemble and check to remove the
lock
2
Shifting
pressure of a
certain gear is
low
1 Damaged piston seal ring of this gear
2 Damaged gasket in the oil lines of this
gear
3 Oil leakage in the oil lines of this gear
1 Change the seal ring
2 Change the gasket
3 Check and remove the leakage
3
The oil of
torque converter
overheats
1 Low oil level in gearbox oil tank
2 High oil level in gearbox oil tank
3 Low shifting pressure and clutch slips
4 T/Q radiator is clogged
5 T/Q operates with high load for a
continuous long time
6 Radiator is not good
1 Add oil to the specified level
2 Drain oil to the specified level
3 Refer the problems 1 and 2
4 Clean or replace the radiator
5 Shut down for cooling
4
Machine can not
move when
engine runs in
high speed
1 Cut-off valve spool of transmission
control valve can’t reset
2 Shift no gear
3 Spring of pressure-regulator valve in
transmission valve is broken
4 Same as 1, 2, 3 and 4 of problem 1
1 Disassemble the cut-off valve, find
out the reasons that spool can’t reset
and remedy
2 Shift gear again or readjust the
gearshift control levers and linkages
3 Change the spring of
pressure-regulator valve
4 Refer to 1, 2, 3 and 4 of problem 1
5
Insufficient
driving force
1 Low shifting pressure
2 High oil temperature of T/Q
3 Damaged T/Q blades
4 Damaged overrunning clutch
5 Insufficient driving force of engine
1 Refer to problems 1 and 2
2 Refer to problems 3
3 Disassemble and check the torque
converter; change blades
4 Disassemble and check free-wheel
clutch, change damage parts
5 Check and maintain the engine
Operation & Maintenance Manual──LG956L Wheel Loader
101
3.8.3 Brake System
No.
Problems
Possible Causes
Remedy
1
Insufficient
brake force
1 Oil leakage of pliers pump
2 Air in brake hydraulic lines
3 Low brake air pressure
4 Over worn leather cup of booster pump
5 Oil leakage from hub to brake plates
6 Worn brake plates
1 Change rectangular sealing ring of
pump
2 Bleed the air out
3 Check the sealing performance of
air compressor, control valve,
storage tank and lines.
4 Change the leather cup
5 Check or replace the seal of hub
6 Change brake plates
2
Failure to release
the brake
normally
1 Wrong position of brake valve spool,
locked piston rod, damaged or faulty
reset spring
2 Improper operation of booster
3 Pliers piston can’t reset
1 Refer to problem 2
2 Check the booster pump
3 Check or replace the rectangular
seal ring
3
Pressure in air
storage tank
drops quickly
after shutting
down (pressure
drop is over 0.1
MPa in 30 min)
1 Inlet valve of foot brake valve is
clogged by dirt as damaged
2 Loose pipe fitting or broken pipes
3 Poor sealing performance of check valve
in combination valve of oil-water
separator
1 Brake continuously several times
to blow the dirt off or change valve
2 Tighten the pipe fitting or change
brake pipes
3 Find out the reasons for sealing
failure and change parts if
necessary
4
Slow rise of
pressure reading
in the brake
gauge
1 Loose pipe fitting
2 Abnormal work of air compressor
3 Inlet valve or diaphragm of brake valve
is not sealed
4 The bleed hole of pressure controlled
valve is clogged or the diaphragm of
check valve leaks air
1 Tighten the fitting
2 Check air compressor
3 Check and clean the inner parts of
brake valve, find out the unsealed
parts then repair
4 Clean air bleed hole, find out the
unsealed reasons of retaining valve
and diaphragm then repair.
Operation & Maintenance Manual──LG956L Wheel Loader
102
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
