Komatsu H75051 Operation & Maintenance Manual page 376

MAINTENANCE PROCEDURE
9.
Remove the bolts (7) (4 pieces) and remove the cover (8).
10. Remove the bolts (9) (4 pieces) and remove the cover
(10).
11. Hold the top of rod (11) and pull it up to take out the strain-
er (12).
12. Remove any dirt stuck to the strainer (12), then wash it in
flushing oil.
If the strainer (12) is damaged, replace it with a new one.
13. Install the strainer (12) to the inside of the tank.
14. While pressing the cover (10), tighten the mounting bolts
(9) evenly.
When doing this, if the O-ring (13) of the cover is damaged
or deteriorated, replace it.
15. Refill with the specified quantity of hydraulic oil through oil
filler port (F), then install the cap.
16. Check the hydraulic oil level.
Check that it is at the specified level by referring to
"METHOD FOR CHECKING OIL LEVEL IN HYDRAULIC
TANK, ADDING OIL (4-46)".
17. Run the engine at low idle, and extend and retract each of
the steering, bucket, and boom cylinders 4 to 5 times, taking care not to move them to the stroke end (stop
them approximately 100 mm short of the stroke end).
NOTICE
If the engine is run at high speed immediately after the startup or a cylinder is pushed up to its
stroke end, air taken inside the cylinder may cause damage to the piston packing, etc.
18. Extend and retract each of the steering, bucket, and boom cylinders to the stroke end 3 to 4 times.
19. Stop the engine, then loosen the cap of the oil filler port
(F).
20. Bleed air from the hydraulic tank. After bleeding air, tighten
the cap of the oil filler port (F).
21. Bleed air while running the engine at low idle.
22. Check the hydraulic oil level.
Check that it is at the specified level by referring to
"METHOD FOR CHECKING OIL LEVEL IN HYDRAULIC
TANK, ADDING OIL (4-46)".
23. Increase the engine speed and bleed air according to the
step 17.
Repeat this work until no air is discharged from the oil filler port (F).
24. Check the hydraulic oil level.
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MAINTENANCE