JLG 450A_AJ Series II Service Manual - Manual (Page 280)

SECTION 5 - HYDRAULICS
5-40 – JLG Lift – 3121290
ASSEMBLY
Refer to Figure 5-76.
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 in cylinder head
gland groove.
Figure 5-78. Rod Seal Installation
IMPROPER SEAL INSTALLATION CAN CAUSE CYLINDER LEAKS AND IMPROPER
CYLINDER OPERATION. ENSURE ‘POLY-PAK’ PISTON SEALS ARE PROPERLY
INSTALLED. REFER TO WIPER SEAL INSTALLATION FOR CORRECT SEAL ORIEN-
TATION.
2. Place new wiper in cylinder head with flat side facing
inside. Use a soft mallet to seat wiper in cylinder head
groove.
3. Install retainer in cylinder head groove.
4. Install O-ring in cylinder head groove.
5. Place new O-rings and back-up ring in outside diameter
cylinder head grooves.
Figure 5-79. Cylinder Head Seals
6. Carefully install head on rod, ensuring wiper and rod
seals are not damaged or dislodged. Push head to rod
end.
7. Place new O-ring and in inner piston diameter groove.
8. Using suitable protection, clamp cylinder rod in a vise or
similar holding fixture as close to piston as possible.
9. Install bushing on rod.
10. Carefully thread piston on cylinder rod. Do not damage
or dislodge O-ring. Torque to 147 ft-lb (200 Nm).
11. Install bushing and sleeve on rod.
12. Install nut and retaining ring on end of rod.
13. Install seal and wear rings in outside piston grooves.
Figure 5-80. Piston Seal Installation