Komatsu WA500-6H Operation & Maintenance Manual page 302

4.9 Service procedure
When required
Bleeding air from hydraulic circuit
1. Lower the bucket to the ground, stop the engine, and wait for
approx. 5 minutes.
2. Check the hydraulic oil level. If the oil level is low, add oil to
the specified level.
For details, see "Check oil level in hydraulic tank, add oil
(4-53)".
REMARK
Do not run the engine at high speed or operate the levers to the
end of the stroke from the beginning. There is danger that the air
inside the cylinder will damage the cylinder packing and reduce
the operating force of the cylinder.
3. Run the engine at low idling and operate each hydraulic cyl-
inders (of steering, bucket and lift arm) 4 to 5 times, stopping
100 mm (3.94 in) from stroke end.
4. Next, operate each hydraulic cylinder (steering, bucket, lift
arm) 3 to 4 times to the end of the stroke.
5. Stop the engine.
6. Loosen air bleed plug (1) of the hydraulic tank and bleed the
air from the hydraulic tank.
7. Tighten air bleed plug (1) of the hydraulic tank.
8. Check the hydraulic oil level. If the oil level is low, add oil to
the specified level.
For details, see "Check oil level in hydraulic tank, add oil
(4-53)".
9. Start the engine and run at low idling.
10. Loosen air bleed plug (1) of the hydraulic tank and bleed the
air from the filter tank.
11. Next, raise the engine speed and repeat the air bleeding
procedure in Steps 3 to 8. Repeat this operation until no
more air comes out from the plug.
If the engine is run at high speed at first, or if the cylinder is
moved to the end of its stroke, the air in the cylinder may
damage the piston packing, etc.
12. After bleeding the air, tighten the air bleeding plug (1).
Tightening torque of the plug:
11.3 ± 1.47 N·m (1.15 ± 0.15 kgf·m, 8.3 ± 1.1 lbft)
13. Check the hydraulic oil level. If the oil level is low, add oil to
the specified level.
For details, see "Check oil level in hydraulic tank, add oil
(4-53)".
4-48
Maintenance
1
GK050214
WA500-6H – VEAM430100