JLG 660SJ Service Manual - Manual (Page 145)

SECTION 5 - HYDRAULICS
3120840 – JLG Lift – 5-13
Main Boom Lift Cylinder Installation
1. Install lift cylinder in place using suitable slings or
supports, aligning attach pin mounting holes on the
upright.
2. Using a suitable drift, drive barrel end attach pin #3
through the mounting holes in the lift cylinder and
the upright. Secure in place with the pin retaining
hardware.
3. Remove cylinder port plugs and hydraulic line caps
and correctly attach lines to cylinder ports.
4. Using auxiliary power extend the cylinder rod until
the attach pin hole aligns with those in the boom.
Using a suitable drift drive cylinder rod attach pin #2
through the aligned holes, taking care to align the
grooved pin holes. Secure the pin in place with
attaching hardware.
5. Remove boom prop and overhead crane. Activate
hydraulic system.
6. Using all applicable safety precautions, operate the
boom functions. Check for correct operation and
hydraulic leaks. Secure as necessary.
7. Check fluid level of hydraulic tank and adjust as nec-
essary.
Upright Level Cylinder Removal
1. With the aid of an assistant, manually override the
Plunger Valve with a pry bar, and from Ground Con-
trol, using auxiliary power, extend the tower tele-
scope out to gain access to leveling cylinder rod
end pin #3.
2. With the main boom positioned and supported as
shown in Leveling Cylinder Removal, prepare to
remove the upright level cylinder.
3. Remove the mounting hardware from pin #1, secur-
ing leveling cylinder to upright.
Figure 5-16. Leveling Cylinder Removal
Figure 5-17. Overriding the Plunger Valve