JLG 450A II Series, Service And Maintenance Manual

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SECTION 5 - HYDRAULICS
3121290 – JLG Lift – 5-11
CLEANING AND INSPECTION
1. Clean all parts in approved cleaning solvent.
2. Inspect cylinder rod for scoring, tapering, ovality, or
other damage. If necessary, dress rod with Scotch Brite
or equivalent. Replace rod if necessary.
3. Inspect threaded portion of rod for excessive damage.
Dress threads as necessary.
4. Inspect inner surface of cylinder barrel tube for scoring
or other damage. Check inside diameter for tapering or
ovality. Replace if necessary.
5. Inspect threaded portion of barrel for damage. Dress
threads as necessary.
6. Inspect piston surface for damage, scoring, and distor-
tion. Dress piston surface or replace piston as needed.
7. Inspect seal and O-ring grooves in piston for burrs and
sharp edges. Dress surfaces as necessary.
8. Inspect cylinder head inside diameter for scoring or
other damage, ovality, and tapering. Replace as needed.
9. Inspect seal and O-ring grooves in head for burrs and
sharp edges. Dress surfaces as necessary.
10. Inspect cylinder head outside diameter for scoring or
other damage, ovality, and tapering. Replace as needed.
11. Inspect rod and barrel bushings for excessive wear or
damage. Replace rod or barrel as necessary.
a. Thoroughly clean rod and barrel steel bushing of
burrs and contamination.
b. Lubricate inside of bushing housing with WD40
before installing composite bushings.
c. Using correct size arbor, press composite bushing
into barrel or rod steel bushing.
NOTE: Lubrication is not required with nickel plated pins and
bearings. Install pin in composite bushings dry.
Figure 5-18. Composite Bushing Installation
12. Inspect travel limiting spacer for burrs and sharp edges.
If necessary, dress inside diameter surface with Scotch
Brite or equivalent.
13. Inspect port block fittings and holding valve. Replace as
necessary. Torque valve to 30-35 ft-lb (41-48 Nm).
14. Inspect oil ports for blockage or presence of dirt or other
contamination. Clean and repair as necessary.