JLG 450A_AJ Series II Service Manual - Manual (Page 253)

SECTION 5 - HYDRAULICS
3121290 – JLG Lift – 5-13
Master Cylinder (450 A/AJ) Without Arctic Package
450A Refer to Figure 5-25. 450AJ refer to Figure 5-26.
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. Support cylin-
der rod as needed.
3. Place cylinder barrel in a suitable holding fixture. Tap
around outside of cylinder head retainer with suitable
hammer to break thread-locking compound.
Figure 5-22. Cylinder Barrel Support
4. Mark cylinder head and barrel with a center punch for
realignment. Unscrew cylinder head with pin-face span-
ner wrench.
Figure 5-23. Cylinder Head Removal
PULLING ROD OFF-CENTER CAN DAMAGE PISTON AND CYLINDER BARREL SURFACES.
USE EXTREME CARE WHEN REMOVING CYLINDER ROD, HEAD, AND PISTON.
5. Clamp barrel securely. Pull rod assembly from barrel.
Figure 5-24. Cylinder Rod Support