JLG 800A_AJ ANSI Service Manual - Manual (Page 287)

SECTION 5 - HYDRAULICS
3120740 – JLG Lift – 5-7
5.6 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 PRESSURE.
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 and fittings from the cylinder port block. Dis-
card o-rings.
4. Place the cylinder barrel into a suitable holding fix-
ture.
5. Mark cylinder head and barrel with a center punch
for easy realignment. Using an allen wrench, loosen
the eight (8) cylinder head retainer cap screws, and
remove cap screws from cylinder barrel.
NOTE: Step 6 applies only to the steer cylinder.
6. Using a spanner wrench, loosen the spanner nut
retainer, and remove spanner nut from cylinder bar-
rel.
7. Attach a suitable pulling device to the cylinder rod
port block end or cylinder rod end, as applicable.
Figure 5-1. Cylinder Barrel Support
Figure 5-2. Cap Screw Removal