Service Manual Instruction Manual

SECTION 5 - HYDRAULICS
3121171 – JLG Lift – 5-3
5.2 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 cyl-
inder. Shut down and disconnect the power source.
Adequately support the cylinder rod, if applicable.
3. If applicable, remove the cartridge-type holding valve
and fittings from the cylinder port block. Discard o-
rings.
4. Place the cylinder barrel into a suitable holding fixture.
NOTE: Step 5 only applies to the steer cylinder.
5. Using a spanner wrench, unscrew the cylinder head
from the barrel.
6. Mark cylinder head and barrel with a center punch for
easy realignment. Using an allen wrench, loosen the
eight (8) cylinder head retainer capscrews, and remove
capscrews from cylinder barrel.
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. Capscrew Removal