Method For Bleeding Air From Hydraulic Circuit - Komatsu PC500LC-10R Shop Manual

30 TESTING AND ADJUSTING

METHOD FOR BLEEDING AIR FROM HYDRAULIC CIRCUIT

Method for bleeding air from main pump
REMARK
Keep the oil filler cap of the hydraulic tank loosened during air bleeding work of the main pump.
1.
Loosen the air bleeder (1) of main pump, and check that
oil oozes out from the air bleeder.
When oil does not flow out, disconnect the drain hose (2)
and then fill up the pump case with oil from the drain hose.
REMARK
• Fix the drain hose fitting in a position higher than the oil
level in the hydraulic tank, and fill up.
• Continue supplying oil until the oil without air flows out.
2.
When the oil without air starts to flow out, tighten air bleed-
er (1).
3
Air bleeder (1):
7.8 to 9.8 Nm {0.8 to 1.0 kgm}
When starting the engine after performing "Bleeding air from main pump", run the engine for 10 minutes with the
fuel control dial at MIN (Low idle) position.
REMARK
Stop the engine once and cancel the automatic warm-up operation by turning the fuel control dial to MAX posi-
tion if it is in operation due to the low engine coolant temperature. (Keep the fuel control dial at MAX (High idle)
position for 3 seconds or more with the starting switch in ON position, and automatic warm-up function will be
canceled.)
Method for bleeding air from cylinder
REMARK
Perform this work before connecting the work equipment if the cylinder has been replaced. Especially, LOWER
side of the boom cylinder cannot be operated to the stroke end with the work equipment installed.
1.
Start the engine, and run it for approximately 5 minutes with the fuel control dial at MIN (Low idle) position.
2.
Repeat raising the boom and lowering it 4 to 5 times while running the engine with the fuel control dial at
MIN (Low idle) position.
REMARK
Be careful to stop the piston rod at approximately 100 mm before each stroke end to avoid relieving.
3.
Repeat raising the boom and lowering it 4 to 5 times while running the engine with the fuel control dial at
MAX (High idle) position.
REMARK
Be careful to stop the piston rod at approximately 100 mm before each stroke end to avoid relieving.
4.
Operate the piston rod to each stroke end to relieve the oil pressure in the circuit.
5.
Bleed air from the arm cylinder and bucket cylinder according to Step 2. to Step 4.
PC500LC-10R
BLEED AIR FROM HYDRAULIC CIRCUIT
30-101