Komatsu PC1250-11 Original Instructions Manual page 350

MAINTENANCE PROCEDURE
2)
If the oil does not ooze out, remove the drain hose
from the hydraulic pump case and fill the pump case
completely with hydraulic oil through drain port (2).
Oil will come out when the drain hose is removed, so
secure the hose fitting at a position higher than the
level of the oil in the hydraulic tank.
3)
After completing the air bleeding operation, tighten the
air bleeder (1) and install the drain hose.
NOTICE
If the drain hose is installed first, oil will spurt out from
the air bleeder (1) hole.
Abnormal heat will be generated if the pump is operat-
ed without filling the pump case with hydraulic oil. It
may cause a premature damage to the pump.
2.
Starting engine
Cancel the automatic warm-up operation, and start the en-
gine. Run the engine at low idle for 10 minutes, and then
start the following work
3.
Bleeding air from cylinder
1)
Loosen the air bleeder (1) on the top face of the return
filter.
2)
Run the engine at low idle, and extend and retract
each cylinder 4 to 5 times, taking care that a cylinder
is not moved to the stroke end. (Stop the cylinder ap-
proximately 100 mm short of its stroke end.)
3)
Next, operate each cylinder 3 to 4 times to each
stroke end.
4)
Finally, operate each cylinder 4 to 5 times to the end
of its stroke to completely remove the air.
5)
Tighten the air bleeder (1) on the top face of the return filter after air bleeding is finished.
NOTICE
If the engine runs at high speed immediately after the startup, or if a cylinder is pushed up to its
stroke end, the air mixed into the cylinder may cause damage to the piston packing, etc.
4.
Bleeding air from swing motor (Perform it only when the oil inside the swing motor case is drained.)
• Front side swing motor
4-34
MAINTENANCE