JLG 660SJ Service Manual - Manual (Page 149)

SECTION 5 - HYDRAULICS
3120840 – JLG Lift – 5-17
4. Remove mounting hardware securing powertrack to
tower boom assembly. After removing mounting
hardware, slide powertrack backward far enough to
move holes and wiring harness to the side to gain
access to telescope cylinder.
5. Tag, disconnect and cap hydraulic hoses to Tower
Telescope Cylinder. Plug cylinder ports.
6. Remove mounting hardware securing upper cylin-
der pin to fly boom. Using a suitable brass drift, drive
out the cylinder rod pin.
7. Remove mounting hardware attaching retaining
plates to base boom and remove plate.
8. Carefully slide the telescope cylinder from the
boom. Place cylinder on a suitable work area.
Tower Telescope Cylinder Installation
1. With the boom positioned as in Figure 5-18., Tower
Telescope Cylinder Removal, slide the telescope cyl-
inder into the boom, aligning the cylinder port block
end with slotted holes in Base Boom. Secure tele-
scope cylinder with mounting hardware.
2. Remove caps and plugs from hydraulic lines and
ports. Properly connect hydraulic lines to cylinder.
Reinstall cover plate.
3. Start engine. With the aid of an assistant, manually
override the plunger valve. Activate Tower telescope
out to align attaching pin holes in Fly Boom. Shut
down engine.
4. Using a brass drift, drive in the attach pin. Secure in
place with mounting hardware.
5. Align holes in base boom and powertrack. Secure
the powertrack with mounting hardware.
6. Remove boom prop and overhead crane. Activate
hydraulic system.
7. Using all applicable safety precautions, operate the
boom functions. Check for correct operation and
hydraulic leaks. Secure as necessary.
8. Check fluid level of hydraulic tank and adjust as nec-
essary.