Komatsu PC138USLC Operation & Maintenance Manual page 306

MAINTENANCE
6. Bleeding air from attachment (when installed)
NOTICE
If the attachment maker specifies an air bleeding procedure for the attachment itself, follow the specified procedure to bleed the
air.
If a breaker or other attachment has been installed, run the engine at low idle and operate the attachment pedal
repeatedly (approx. 10 times) until the air has been bled from the attachment circuit.
NOTICE
After completing the air bleeding operation, stop the engine, and leave the machine for 5 minutes before starting operations.
This will remove the air bubbles in the oil inside the hydraulic cylinders.
Check that there is no leakage of oil and wipe off any oil that has been spilled.
MAINTENANCE PROCEDURE
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