Oshkosh JLG 1500SJ, Service And Maintenance Manual

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SECTION 5 - BASIC HYDRAULIC INFORMATION & HYDRAULIC SCHEMATICS
3121262 – JLG Lift – 5-91
8. Using suitable protection, clamp the cylinder rod in a
vise or holding fixture as close to the piston as possible.
9. Loosen and remove the lock nut that secures the piston
to the cylinder rod.
10. Remove the piston from the cylinder rod.
11. Remove and discard the piston o-rings, seal rings, and t-
seal.
12. Remove the rod from the holding fixture. Remove the
cylinder head. Discard all seals on the cylinder head.
CLEANING AND INSPECTION
1. Clean all parts thoroughly in an approved cleaning sol-
vent.
2. Inspect the 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 and scoring and for
distortion. Dress piston surface or replace piston as nec-
essary.
7. Inspect threaded portion of piston for damage. Dress
threads as necessary.
8. Inspect seal and o-ring grooves in piston for burrs and
sharp edges. Dress applicable surfaces as necessary.
9. Inspect cylinder head inside diameter for scoring or
other damage and for ovality and tapering. Replace as
necessary.
10. Inspect threaded portion of head for damage. Dress
threads as necessary.
11. Inspect seal and o-ring grooves in head for burrs and
sharp edges. Dress applicable surfaces as necessary.
12. Inspect cylinder head outside diameter for scoring or
other damage and ovality and tapering. Replace as nec-
essary.
13. If applicable, inspect rod and barrel bearings for signs of
correct excessive wear or damage. Replace as necessary.
a. Thoroughly clean hole, (steel bushing) of burrs, dirt
etc. to facilitate bearing installation.
b. Inspect steel bushing for wear or other damage. If
steel bushing is worn or damaged, rod/barrel must
be replaced.
c. Lubricate inside of the steel bushing with WD40
prior to bearing installation.
d. Using an arbor of the correct size, carefully press the
bearing into steel bushing.
NOTE: Install pin into the composite bearing dry. Lubrication is
not required with nickel plated pins and bearings.
14. Inspect the oil ports for blockage or the presence of dirt
or other foreign material. Repair as necessary.
15. If applicable, inspect piston rings for cracks or other
damage. Replace as necessary.
ASSEMBLY
NOTE: Prior to cylinder assembly, ensure that the proper cylinder
seal kit is used. See your JLG Parts Manual.
Apply a light film of hydraulic oil to all components prior to
assembly.
1. A special tool is used to install a new rod seal into the
applicable cylinder head gland groove.
W H E N I N S TA L L I N G N E W S E A L S , E N S U R E S E A L S A R E
INSTALLED PROPERLY. IMPROPER SEAL INSTALLATION
Figure 5-110. Composite Bearing Installation
Figure 5-111. Rod Seal Installation