Tower Lift Cylinder - JLG 450A series II Service And Maintenance Manual

SECTION 5 - HYDRAULICS

Tower Lift Cylinder

DISASSEMBLY
Refer to Figure 5-5.
CONTAMINATION MAY DAMAGE EQUIPMENT. DISASSEMBLE CYLINDER ON A
CLEAN WORK SURFACE IN A DIRT FREE WORK AREA.
1. Connect a suitable auxiliary hydraulic power source to
cylinder port block fitting.
DO NOT FULLY EXTEND CYLINDER TO THE END OF STROKE. RETRACT CYLINDER
SLIGHTLY TO AVOID TRAPPING PRESSURE.
2. Operate hydraulic power source and extend cylinder.
Shut down and disconnect power source. Adequately
support cylinder rod, if applicable.
3. Remove cartridge-type counterbalance valve and fittings
from cylinder port block. Discard O-rings.
4. Place cylinder barrel in a suitable holding fixture. Tap
around outside of cylinder head retainer with a suitable
hammer to break thread-locking compound.
Figure 5-2. Cylinder Barrel Support
5-4
5. Mark cylinder head and barrel with a center punch for
realignment. Remove eight cylinder head cap screws.
Figure 5-3. Cylinder Head Removal
PULLING ROD OFF-CENTER CAN DAMAGE PISTON AND CYLINDER BARREL SURFACES.
USE EXTREME CARE WHEN REMOVING CYLINDER ROD, HEAD, AND PISTON.
6. Clamp barrel securely. Pull rod assembly and cylinder
head from barrel.
7. Protect cylinder rod from damage and clamp in a vise or
holding fixture as close to piston as possible.
Figure 5-4. Cylinder Rod Support
– JLG Lift – 3121290