JLG Lull 1044C-54 II Series Service Manual page 164

Boom and Transfer
6-22
WARNING: The counterbalance valve cartridge traps hydraulic pressure
in the cylinder. Wear proper eye and hand protection when
removing counterbalance valve cartridges. Hydraulic fluid
under pressure can be injected under skin or into eyes,
resulting in serious personal injury or death.
a. Place socket wrench over counterbalance valve cartridge (Item 5).
Wrap a clean shop rag around the socket to cover the area of the
counterbalance valve cartridge.
b. Carefully and slowly, turn cartridge out of manifold block (Item 2) to
release pressure in cylinder.
3. Remove the counterbalance valve cartridge.
4. Slowly extend and retract cylinder by hand to remove most of the
hydraulic oil.
5. Remove one (1) set screw (Item 3) securing rod bearing head
(Item 13) to barrel.
6. Remove cylinder rod (Item 9) from cylinder barrel (Item 7).
CAUTION: To prevent possible damage to components, support rod and
head; do not wiggle rod or head back and forth during
removal.
7. Remove rod nut (Item 6), piston (Item 11), tube (Item 12), and rod
bearing head from cylinder rod.
8. Remove the two (2) connectors (Item 1) from the cylinder manifold
block (Item 2).
9. Inspect bushings for damage. The following steps are necessary if
bushing(s) need to be replaced:
a. Remove bushing (Item 8) from cylinder barrel and/or remove
bushing (Item 2) from cylinder rod using a bushing driver and
hammer or press. Drive one bushing all the way through to remove
other bushing.
b. Install new bushings so they are flush with outer edge boss to 0.02"
below.
c. To ensure proper lubrication, make sure an adequate amount of
grease is applied to the grease fitting(s) after cylinder is reinstalled
on machine.
10. Remove all O-rings, wear rings, and backup rings from cylinder
components and discard.
11. Thoroughly clean components with solvent and dry with compressed
air.
12. Inspect inner surface of barrel, outer surface of piston, and length of
rod for scratches and scoring. If barrel, piston, or rod is damaged, it
must be replaced.
13. Check condition of threads on rod, nut, and setscrew. Do not attempt to
repair damaged threads.
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