Komatsu D31EX-21, Operation & Maintenance Manual, Page: 234 / 256

SERVICE PROCEDURE
MAINTENANCE
4-54
7. Using the filter wrench, turn filter cartridges (5) and (6) to
the left and remove them.
8. Remove 4 bolts (7), then lift up the flange portion of piping
(8).
REMARK
Lift up the flange to take out the strainer. Turn the flange by uti-
lizing the slack of the rubber hose connected to the pipe.
9. Remove 2 screws (9), then take out strainer (10).
10. Remove any dirt stuck to strainer (10), then wash it in clean
diesel oil or flushing oil.
11. Assemble strainer (10), tighten screws (9), then assemble
piping (8) with bolts (7).
12. Clean the filter holder, fill the new filter cartridge with oil,
then coat the seal and thread of the filter cartridge with oil
(or coat thinly with grease) and install.
13. After the packing surface of the cartridge touches the sealing surface of the filter holder, tighten the cartridge
further by about 2/3 turns.
Use Komatsu genuine cartridge.
14. Refill the specified quantity of oil through oil filler (F).
15. After adding oil, check that the oil is at the correct level.
For details, see “CHECK OIL LEVEL IN HYDRAULIC TANK, ADD OIL (3-68)“.
16. Install the cover at the rear of the machine.
17. After replacing hydraulic oil and cleaning or replacing filter element and strainer, bleed air from the circuit.
For details of the method of bleeding the air from the hydraulic circuit, see “PROCEDURE FOR BLEEDING
AIR IN HYDRAULIC SYSTEM (4-34)“.
O-ring