JLG 740AJ, Service And Maintenance Manual

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SECTION 5 - BASIC HYDRAULIC INFOR M ATION AND SCHE M ATICS
5-40 3121160
8. Using suitable protection, clamp the cylinder rod in a
vise or similar holding fixture as close to the piston as
possible.
9. Remove capscrews from drilled holes.
10. Insert the capscrews in the threaded holes in the outer
piece of the tapered bushing. Progressively tighten the
capscrews until the bushing is loosen on the piston.
11. Remove the bushing from the piston.
12. Screw the piston counterclockwise by hand and remove
the piston from cylinder rod.
13. Remove and discard the piston hydrolock seals, guide-
lock rings, o-ring, and backup rings.
14. Remove piston spacer from rod.
15. Remove the rod from the holding fixture. Remove the
cylinder head gland. Remove and discard the o-rings,
backup rings, wear ring, rod seal, and wiper seal.
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 inner side of steel bushing with 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.
TAPERED
BUSHING
ROD
CAPSCREW
PISTON
Figure 5-80. Tapered Bushing Removal