Komatsu PC88MR-10 Shop Manual page 416

30 Testing and adjusting
Hydraulic system
2. Starting the engine
When starting the engine after performing step 1,
keep it at low idle for 10 minutes.
a When performing the automatic warm-up
operation while engine coolant temperature
is low, stop the engine once and cancel the
automatic warm-up function with fuel dial.
(Turn the starting switch to ON position and
keep the fuel dial at MAX position for 3
seconds or more, and automatic warm-up
function will be canceled.)
3. Bleeding air from cylinders
a When the cylinder has been replaced, bleed
air from the cylinder before connecting the
work equipment. Especially, the LOWER
side of the boom cylinder does not operate to
the stroke end with the work equipment
installed.
1) Start the engine and run it at low idle for
approximately 5 minutes.
2) While running the engine at low idle, raise
and lower the boom 4 to 5 times.
a Stop the piston rod at approximately 100
mm before stroke end to avoid relieving.
3) While running the engine at high idle,
perform the operation in step 2).
4) While running the engine at low idle, move
the piston rod to the stroke end to relieve the
circuit.
5) Bleed air from the arm and bucket cylinders
according to steps 2) to 4).
4. Bleeding air from swing motor
a Bleed air only when the oil inside the swing
motor case is drained.
a If the air is not bled from the swing motor and
the machine is operated, the motor bearings
may be damaged.
1) Run the engine at low idle, loosen drain hose
(2), and tighten it when oil flows out.
a Do not perform the swing operation
during this work.
2) Run the engine at low idle and slowly swing
at least 2 times to the right and left.
30-66
5. Bleeding air from travel motor
1) Remove the travel motor cover and
disconnect motor drain hose (3).
2) Start the engine, and run it at low idle, and
check that the oil flows out of nipple (4).
3) Connect hose (3) and restore the machine.
6. Check of oil level and operation
1) Start the engine, retract the arm and bucket
cylinders fully, lower the work equipment to
the ground, and stop the engine.
2) Check the oil level by sight gauge (5) at the
rear of the hydraulic tank.
a If the oil level is below line L, add new oil.
a Since the oil level varies according to the
oil temperature, use the followings as a
guide.
Oil temperature 10 to 30°C: Halfway
between H and L
PC88MR-10