Oshkosh JLG 1500SJ, Service And Maintenance Manual

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SECTION 5 - BASIC HYDRAULIC INFORMATION & HYDRAULIC SCHEMATICS
5-74 – JLG Lift – 3121262
Boom Lift Cylinder
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 cyl-
inder. Shut down and disconnect the power source.
Adequately support the cylinder rod, if applicable.
3. Remove the check valve, counterbalance valve, and
pressure regulator valve from the cylinder port block.
Discard o-rings.
4. Place the cylinder barrel into a suitable holding fixture.
5. Mark cylinder head and barrel with a center punch for
easy realignment. Using an allen wrench, loosen the cyl-
inder head retainer capscrews, and remove capscrews
from cylinder barrel.
6. Attach a suitable pulling device to the cylinder rod end.
EXTREME CARE SHOULD BE TAKEN WHEN REMOVING THE
CYLINDER 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, carefully withdraw the
complete rod assembly from the cylinder barrel.
Figure 5-72. Cylinder Barrel Support
Figure 5-73. Cap Screw Removal
Figure 5-74. Cylinder Rod Support