JLG Lull 1044C-54 II Series Service Manual page 295

Disassembly, Frame Tilt Cylinder
Cleaning and Inspection, Frame Tilt Cylinder
31200079
(Ref. Fig. 7-7) The following steps are required to disassemble the frame
tilt cylinder.
1. Mount or support cylinder vertically, with rod end down. Hydraulic oil in
cylinder will drain out during disassembly. Place a suitable pan or tray
under the cylinder.
2. Remove counterbalance valve (Item 3).
WARNING: The counterbalance valve cartridges trap hydraulic pressure
in the frame tilt 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.
3. Slowly extend and retract cylinder by hand to remove most of the
hydraulic oil.
4. Remove one (1) set screw (Item 7) securing head (Item 12) to barrel
(Item 2).
5. Pull rod (Item 11) out to help remove head. Support rod and head
during removal to prevent damage. Do not wiggle rod or head back and
forth to remove; this may damage the components.
6. Remove rod nut (Item 10), piston (Item 9), tube (Item 8), and head
from rod.
7. Remove two (2) O-ring plugs (Item 4).
8. Remove fittings (Item 6).
9. Using a large, flat bladed screw driver, remove two (2) orifices (Item 5).
10. If the bushings need to be replaced, see "Bushing Replacement"
below.
1. Remove all O-rings, wear rings, and backup rings from cylinder
components and discard.
2. Thoroughly wash components in solvent and dry with compressed air.
3. Inspect inner surface of barrel, outer surface of piston, and length of
the rod for scratches and scoring. If barrel, piston, or rod is damaged, it
must be replaced.
4. Check condition of threads on rod, nut, and capscrews. Replace as
necessary. Do not attempt to repair damaged threads.
Frame Tilt and Oscillation
7-13