JLG 400S Service And Maintenance Manual page 409

8. Using suitable protection, clamp the cylinder rod in a
vise or similar holding fixture as close to the piston as
possible.
9. Loosen and remove the setscrew and ball which
attaches the piston to the rod.
10. Screw the piston counterclockwise, by hand, and
remove the piston from cylinder rod.
11. Remove and discard the piston seal and o-ring.
12. Remove the rod from the holding fixture. Remove the
cylinder head. Discard the o-rings, backup rings, rod
seal, bearing, retaining ring, and wiper seal.
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SECTION 5 - BASIC HYDRAULICS INFORMATION & SCHEMATICS
CLEANING AND INSPECTION
1. Clean all parts thoroughly in an approved cleaning
solvent.
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
necessary.
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,
tapering, ovality or other damage. Replace if 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,
tapering or ovality other damage. Replace if necessary.
13. 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
bearing installation.
d. Using an arbor of the correct size, carefully press the
bearing into steel bushing.
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