jcb JS70, Service Manual

Page: 35 / 385

5 - 3
Section 3 Routine Maintenance
9803/6020
Section 3
5 - 3
Issue 1
Hydraulics (continued)
Air Bleeding Procedures (continued)
Bleeding Air from the Rams
If air is not bled from the rams when replaced or repaired,
the piston and/or seals may be damaged.
1 Prepare the Machine
Idle the engine at low speed and extend and retract
each ram 4 or 5 times, stopping the ram 100 mm
before the end of each stroke.
2 Bleeding
Operate each ram 3 or 4 times over the full stroke in
both directions to completely bleed the air.
Bleeding Air from the Slew Motor
If air is not completely bled from the slew motor the motor
bearing or other parts may be damaged.
1 Prepare the Machine
Position the machine on level ground. Stop the
Engine.
2 Locate the Slew Motor
The slew motor is mounted on the slew gearbox.
Refer to the
Component Location Diagram at the
end of this section.
3 Bleeding the Slew Motor
a Start the engine and idle at low speed.
b Loosen air bleeding plug A and check that oil
seeps out (the illustration right shows the top of
the slew motor with the arrow indicating the front
of the machine).
Note: Do not operate any other equipment .
c If no oil seeps out, stop the engine and remove air
bleeding plug
A . Fill the motor case with hydraulic
oil.
d Temporarily tighten air bleeding plug A .
e Idle the engine at low speed again. Slightly loosen
air bleeding plug
A and continue to run until oil
runs out of the port.
4 Sealing the System
a Tighten air bleeding plug A firmly.
b Idle the engine at low speed and slowly slew the
machine left to right evenly, two or more times.
A