JLG 680S, Service And Maintenance Manual

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SECTION 5 - BASIC HYDRAULICS INFORMATION & SCHEMATICS
3121234 5-11
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 o-rings, hydrolock seals,
guidelock rings, and backup rings.
14. Remove setscrew and piston spacer from the rod.
15. Remove the rod from the holding fixture. Remove the
cylinder head gland. Discard the o-rings, backup rings,
rod seals, wear rings, and wiper seals.
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 piston surface for damage and scoring and for
distortion. Dress piston surface or replace piston as nec-
essary.
6. Inspect threaded portion of piston for damage. Dress
threads as necessary.
7. Inspect seal and o-ring grooves in piston for burrs and
sharp edges. Dress applicable surfaces as necessary.
8. Inspect cylinder head inside diameter for scoring, taper-
ing, ovality or other damage. Replace if necessary.
9. Inspect seal and o-ring grooves in head for burrs and
sharp edges. Dress applicable surfaces as necessary.
10. Inspect cylinder head outside diameter for scoring,
tapering, ovality or other damage. Replace if necessary.
11. If applicable, inspect rod and barrel bearings for signs of
correct excessive wear or damage. Replace if 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 prior to bear-
ing installation.
d. Using an arbor of the correct size, carefully press the
bearing into steel bushing.
Figure 5-19. Tapered Bushing Removal