5-47
MAINTENANCE
8. Remove the return filter (7).
9. Place a pan for catching the waste oil
under the drain plug (9).
10.
Loosen the drain plug (9) and drain the
hydraulic oil.
11.
Loosen the hose bands and remove the
hose (4).
12.
Loosen the bolts and remove the flange
(10).
13.
Remove the suction strainer (11) and
clean it.
14.
Clean the inside of the hydraulic tank.
15. Install the suction strainer (11) to the
flange (10).
16. Reinstall the flange (10) and the hose (4)
to their original positions.
17.
Install a new return filter to the flange (6).
18. Reinstall the flange (6) to their original
positions.
19.
Tighten the drain plug (9).
20. Add hydraulic oil from the hole of plug (1)
up to the level between the upper limit
(H) and the lower limit (L) in the sight
gauge (8).
EVERY 4000 HOURS
21. Tighten the plug (1).
22. Bleed air from the hydraulic oil circuit
following “Bleeding air” below.
23. Set the machine to the hydraulic oil level
inspection posture and inspect the oil
level when the oil temperature drops.
Refer to “Inspecting the hydraulic oil tank
level and replenishing” on page 5-19.
Bleeding air
IMPOR
TANT: After replacing the hydraulic
oil, bleed air from the hydraulic circuits
and hydraulic devices. Failure to do so
may damage the hydraulic devices.
• Cylinders
1. Start the engine, let it run at a low-idling
speed for 10 minutes.
2.
Maintain the engine at low idle, then
extend and retract each cylinder 4 or 5
times, without let them reach the stroke
end.
3.
Run the engine at high speed, then extend
and retract each cylinder 4 or 5 times,
without let them reach the stroke end.
4. Set the engine back to a low idle, then
extend and contract all the cylinders 4 or 5
times to the stroke ends.