Komatsu PC138USLC Operation & Maintenance Manual page 335

MAINTENANCE PROCEDURE
METHOD OF RELEASING PRESSURE IN HYDRAULIC CIRCUIT
NOTICE
Carry out the following procedure to operate the work equipment control lever fully to the front, rear, left, and right within 15
seconds of stopping the engine.
When the engine stops, the pressure in the accumulator gradually goes down, so the pressure can only be released immediately
after the engine is stopped.
1. Place the work equipment on the ground. Close the crusher
attachment jaws, etc.
2. Stop the engine.
3. Turn the starting switch to the ON position (B).
4. Set the lock lever to the FREE position (F), then operate each
work equipment control lever and attachment control pedal (if
equipped) fully to the front, rear, left, and right to release the
pressure in the hydraulic circuit.
5. Set the lock lever to the LOCK position (L) to lock the work
equipment control levers and attachment control pedal (if
equipped).
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MAINTENANCE