JLG 1250AJP Service Manual - Manual (Page 400)

SECTION 5 - HYDRAULICS
5-46 – JLG Lift – 3121171
Air Purge Procedure for Non-Calibrated
Machines
1. Loosen the hoses on Port #2 (side) of Tower Lift and
Tower Telescope enable valves. This is not neces-
sary on Main Lift Enable Valve because the orienta-
tion of the valve allows the air to escape.
2. Operate the Main Telescope in until oil appears at
Port #2 of both valves.
3. Tighten both hoses.
4. Raise the Main Boom to approximately 10° above
horizontal.
5. Operate the Tower Lift for 25 of the following cycles:
a. Raise the Tower Boom approximately 18”
b. Pause for approximately 2 seconds.
c. Lower the Tower Boom to the boom rest.
d. Pause for approximately 2 seconds.
6. Operate the Tower Telescope for 25 of the following
cycles:
a. Extend the Tower Booms approximately 2’
b. Pause for approximately 2 seconds
c. Fully retract the Tower Booms.
d. Pause for approximately 2 seconds.
Air Purge Procedure for Calibrated
Machines
1. Loosen the hoses on Port #2 (side) of Tower Lift and
Tower Telescope enable valves. It is not necessary
on Main Lift Enable Valve because the orientation of
the valve allows the air to escape.
2. Operate the Main Telescope in until oil appears at
Port #2 of both valves.
3. Tighten both hoses.
4. Operate Tower Lift up until Tower Booms begins to
Telescope.
5. If an ENABLE VALVE STUCK OPEN fault occurs;
a. Cycle power.
b. Use Auxiliary Power to raise the Tower Boom
until the Tower Telescope starts to move.
6. Under engine power, operate the Tower Lift for 25 of
the following cycles:
a. Raise the Tower Boom approximately 18”.
b. Pause for approximately 2 seconds.
c. Lower the Tower Boom 18”.
NOTE: Do not pause at this reversal. Quickly switch from
Tower down to Tower up.
7. Raise the Tower Boom 18”, then lower it and stop
before the boom is on the boom rest.
8. Command Tower Boom up until boom moves.
9. Check for faults.
10. If there are faults, continue cycling as in Step #6
until there are no faults after completing Steps #7
and #8.
11. If there are no faults, position the machine in the
stowed position.