JLG 45e Service Manual - Manual (Page 46)

SECTION -
-20 – JLG Lift – 3120861
2.10 CYLINDER REPAIR.
NOTE: The following are general procedures that apply to
all of the cylinders on this machine. Procedures that
apply to a specific cylinder will be so noted.
Disassembly.
DISASSEMBLY OF THE CYLINDER SHOULD BE PERFORMED ON
A CLEAN WORK SURFACE IN A DIRT FREE WORK AREA.
1. Connect a suitable auxiliary hydraulic power source
to the cylinder port block fitting.
DO NOT FULLY EXTEND CYLINDER TO THE END OF STROKE.
RETRACT CYLINDER SLIGHTLY TO AVOID TRAPPING PRES-
SURE.
2. Operate the hydraulic power source and extend the
cylinder. Shut down and disconnect the power
source. Adequately support the cylinder rod, if appli-
cable.
3. If applicable, remove the cartridge type holding
valve, manual descent valve, and fittings from the
port block. Discard o-rings.
4. Place the cylinder barrel into a suitable holding fix-
ture. Tap around outside of cylinder head retainer
with a suitable hammer to shatter loctite.
5. Using a suitable chain wrench, loosen the cylinder
head retainer, if applicable, and/or cylinder head
gland, and remove from cylinder barrel.
NOTE: Steer cylinder has cylinder head retainer at both
ends. Remove both retainers.
6. Attach a suitable pulling device to the cylinder rod
port block end or cylinder rod end, as applicable.
EXTREME CARE SHOULD BE TAKEN WHEN REMOVING THE CYL-
INDER ROD, HEAD AND PISTON. AVOID PULLING THE ROD OFF
CENTER, WHICH COULD CAUSE DAMAGE TO THE PISTON AND
CYLINDER BARREL SURFACES.
7. With the barrel clamped securely, apply pressure to
the rod pulling device and carefully withdraw the
complete rod assembly from the cylinder barrel.
ONCE THE HEAD GLAND HAS CLEARED THE CYLINDER CASE
MOUTH, THE ROD MUST BE SUPPORTED CLOSE TO THE CYLIN-
DER CASE PRIOR TO THE PISTON BEING PULLED PAST THE
CYLINDER CASE THREADS, AND/OR THE PISTON AND PISTON
SEALS.
NOTE: Step (8) applies to the steer cylinder.
8. Remove the remaining head gland from the barrel if
you have not already done so.
9. Using suitable protection, clamp the cylinder rod in
a vise or similar holding fixture as close to the piston
as possible.
10. Remove the set screw(s) if applicable, and nut which
attach the piston and spacer(s), if applicable, to the
rod, and remove piston and spacers. Discard self
locking set screws.
NOTE: Step (11) applies to the slave leveling and master
cylinders. (Cylinders built from 12/94 to present)
11. Remove the set screw, and nut which attach the pis-
ton and spacer to the rod. Using a suitable nylon
strap wrench loosen piston and remove piston and
spacers. Discard self locking set screws
Figure 2-12. Removal of Cylinder Retainer.
Figure 2-13. Removal of Set Screws.