JLG 450A_AJ Series II Service Manual - Manual (Page 263)

SECTION 5 - HYDRAULICS
3121290 – JLG Lift – 5-23
Telescope Cylinder
Refer to Figure 5-45.
DISASSEMBLY
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 holding 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 5-43. Cylinder Barrel Support
5. Use a strap wrench to remove cylinder end cap.
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 from barrel.
Figure 5-44. Cylinder Rod Support
7. Using suitable protection, clamp cylinder rod in a vise or
similar holding fixture as close to piston as possible.
8. Remove nut securing piston to rod and remove piston.
9. Remove and discard piston seals and lock rings.
10. Remove piston O-ring from rod (450 AJ only).
11. Loosen setscrew (450A only) on spacer. Remove spacer
from rod.
12. Remove rod from holding fixture. Remove cylinder head
and end cap. Discard O-rings, back-up rings, rod seals,
and wiper seals.