CG958G Wheel Loader. Manual - part 16
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4. Selector valve: 7130-B
The selector valve adopted for the loader is pilot-controlled hydraulic multi-path change valve, mainly
consisting of tipping couplet, are moving couplet, main overflow valve, overload valves, inlet check valve, oil
filling valve for movable arm chamber, etc. System pressure is adjusted via overflow cock at the inlet.
Tipping couplet is equipped with two overload valves to protect tipping cylinder and pipelines.
When the selector valve plug is in neutral position, oil inlet and outlet are connected, so there is no operation
of working unit.
Turn the tipping handle, pressure oil in proportion to travel is output by pilot-controlled valve to apply a force
on one end of selector valve plug to slowing reverse the plug. As pressure gradually accumulates at oil inlet
of selector valve, oil inlet check valve is opened, and pressure oil enters working port to activate working
unit.
III. Troubleshooting of working hydraulic system
No. Symptoms
Causes
Solutions
A Insufficient
lifting
force of movable
arms or
insufficient bucket
turning force
1． Cylinder oils seal is damaged
2． Clearance between selector valve rod
and valve body exceeds limits due to
overwearing
3． Oil leakage in piping system
4． Severe internal leakage of working
pump
5． Low pressure at safety valve
1． Replace oil seal
2． Replace selector valve or check
and repair valve plug
3． Check for cause of leakage and
eliminate it
4． Replace working pump
5． Adjust system to nominal value
6． Replace oil and clean oil filter