JLG 450A II Series, Service And Maintenance Manual

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SECTION 5 - HYDRAULICS
5-12 – JLG Lift – 3121290
ASSEMBLY
NOTE: Use proper cylinder seal kit for cylinder assembly. See your
JLG Parts Manual.
Apply a light film of hydraulic oil to all components before
assembly.
1. Use seal tool to install new rod seal (18) in cylinder head
gland groove.
Figure 5-19. Rod Seal Installation
IMPROPER SEAL INSTALLATION CAN CAUSE CYLINDER LEAKS AND IMPROPER
C YLINDER OPERATION.INSTALL SEAL (18) AND WIPER (19) IN CYLINDER
HEAD GROOVE. INSTALL NEW WEAR RING (16) IN CYLINDER HEAD GROOVE.
INSTALL NEW O-RING (17) IN OUTSIDE DIAMETER GROOVE OF CYLINDER
HEAD.
Figure 5-20. Head Seals
2. Slide End Cap on rod with threads facing open end of
rod.
3. Carefully install assembled head (5) on rod. Make sure
wiper and rod seals are not damaged or dislodged. Push
head along rod to rod end.
4. Carefully slide spacer on rod to marked position. Apply
locking compound to setscrew. Tighten setscrew.
5. Insert new O-ring (15) in piston (4) groove. Install seal
(14) on center of piston. Install wear rings (13) on each
end of piston.
Figure 5-21. Piston Seal Kit Installation
6. Using suitable protection, clamp cylinder rod in a vise or
similar holding fixture as close to piston as possible.
7. Carefully slide assembled piston on cylinder rod. Make
sure O-ring is not damaged or dislodged.
8. Apply locking primer and locking compound to rod
threads. Install nut and torque to 200 ft-lb (270 Nm).
Tighten setscrew to 100 in-lb (11 Nm).
9. Remove cylinder rod from holding fixture.
10. Position cylinder barrel in a suitable holding fixture.
INSTALLING ROD OFF-CENTER CAN DAMAGE PISTON AND CYLINDER BARREL SURFACES.
USE EXTREME CARE WHEN INSTALLING CYLINDER ROD, HEAD, AND PISTON.
11. Clamp barrel clamped securely and support rod. Insert
piston end into barrel cylinder. Do not damage or dis-
lodge piston loading O-ring and seal ring.
12. Continue pushing rod and cylinder head into barrel.
13. Apply locking compound to barrel threads and tighten
end cap using strap wrench.