JLG 800A_AJ Service Manual - Manual (Page 307)

SECTION 5 - HYDRAULICS
3120858 – JLG Lift – 5-25
Upper Boom Telescope Cylinder Installation
1. Attach a hydraulic power supply to the telescope
cylinder ports. Using suitable supports or lifting
devices at each end of the cylinder, extend the rod
so that the cylinder pin attach holes are the same
distance apart as the boom pin attach holes.
2. Using suitable lifting equipment, carefully insert the
cylinder into the boom assembly.
3. Install the cylinder into the boom assembly.
4. Remove the lifting devices from the telescope cylin-
der.
5. Carefully install telescope cylinder rod pin #1
through the fly boom and secure it with the retaining
rings.
6. Carefully install the telescope cylinder barrel end
support into mounting block in base boom and
secure with blocks and bolts. Use Loctite #242 on
bolts. Shim as necessary.
7. Remove applicable hydraulic line and port caps and
correctly connect the hydraulic lines to the tele-
scope cylinder. Ensure all hoses are correctly
routed.
8. Extend the upper lift cylinder using the auxiliary con-
trol to align with rod end hole in main base boom
9. Carefully insert the upper lift cylinder rod end pin
through the base boom and install the mounting
hardware.
10. Remove boom prop and overhead crane. Activate
hydraulic system.
11. Using all applicable safety precautions, operate the
boom functions. Check for correct operation and
hydraulic leaks. Secure as necessary.
12. Check fluid level of hydraulic tank and adjust as nec-
essary.
Upper Lift Cylinder Removal
1. Place the machine on a flat and level surface. Attach
a suitable lifting device and sling, sufficient to lift the
upper boom assembly, to the approximate center of
the upper boom assembly.
2. Remove the hardware retaining the upper lift cylin-
der rod attach pin to the boom. Using a suitable
brass drift, drive out the cylinder rod attach pin.
3. Using auxiliary power, retract the lift cylinder rod
completely.
4. Disconnect, cap and tag the upper boom lift cylinder
hydraulic lines and ports.
5. Attach a suitable lifting device and sling to the upper
lift cylinder
6. Remove barrel end attach pin retaining hardware.
7. Using a suitable brass drift drive out the barrel end
attach pin from the tower upright.
8. Raise the upper boom assembly with the lifting
device and sling to allow enough space to remove
the upper lift cylinder from the upright top.
9. Carefully lift the cylinder clear of the boom assembly
and lower to the ground or suitably supported work
area.
10. Lower the boom assembly to the rest position.