JLG 450AJ ANSI Service Manual - Manual (Page 25)

SECTION 2 - PROCEDURES
3120749 – JLG Lift – 2-7
13. Install wear pads at end of base boom section.
Using shims, adjust the adjustable wear pads to
zero clearance. Adjust pads alternately side to side,
so that fly boom section is centered in base boom
section.
14. Retract boom section fully. Using shims, adjust wear
pads at aft end of boom section to zero clearance.
Adjust pads alternately side to side, so that fly boom
section is centered in base boom section.
15. Disconnect auxiliary power source from telescope
cylinder.
Installation of the Boom Assembly.
1. Using suitable lifting equipment, position boom
assembly on turntable so that boom pivot holes in
both boom and turntable are aligned.
2. Install boom pivot pin, ensuring that location of the
hole in pivot pin aligns with attach point on upright.
3. Using all applicable safety precautions, operate lift-
ing equipment in order to position boom lift cylinder
and level link so that holes in cylinder rod end and
level link are aligned with the one in the turntable.
Insert cylinder pins.
4. If necessary, gently tap pins into position with a soft
headed mallet, ensuring that attach holes in pins are
aligned with attach holes in boom structure. Secure
with hardware.
5. Connect all hosing and wiring.
6. Install the platform to the boom assembly.
7. Connect all hosing and wiring at platform control
station.
8. Using all safety precautions, operate machine sys-
tems and extend and retract boom for four or five
cycles.
9. Shut down machine systems and check for leakage.
2.7 CYLINDER CHECKING PROCEDURE
IF PERFORMING MAINTENANCE ON THE BOOM CYLINDERS, DO
NOT USE A LIFTING DEVICE TO LIFT THE BOOMS UNLESS THE
HOLDING VALVES HAVE BEEN REMOVED FIRST. FAILURE TO DO
SO WILL RESULT IN SEVERE DAMAGE TO THE BOOM.
NOTE: Cylinder check must be performed anytime a system
component is replaced or when improper system
operation is suspected.
Cylinders Without Counterbalance Valves -
Master Cylinder and Steer Cylinder
1. Using all applicable safety precautions, activate
engine and fully extend cylinder to be checked. Shut
down engine.
2. Carefully disconnect hydraulic hoses from retract
port of cylinder. There will be some initial weeping of
hydraulic fluid which can be caught in a suitable
container. After the initial discharge, there should be
no further drainage from the retract port.
3. Activate engine and extend cylinder.
4. If cylinder retract port leakage is less than 6-8 drops
per minute, carefully reconnect hose to port and
retract cylinder. If leakage continues at a rate of 6-8
drops per minute or more, cylinder repair must be
made.
5. With cylinder fully retracted, shut down engine and
carefully disconnect hydraulic hose from cylinder
extend port.
6. Activate engine and retract cylinder. Check extend
port for leakage.
7. If extend port leakage is less than 6-8 drops per
minute, carefully reconnect hose to extend port,
than activate cylinder through one complete cycle
and check for leaks. If leakage continues at a rate of
6-8 drops per minute or more, cylinder repairs must
be made.