Tapered Bushing Removal - JLG 450A series II Service And Maintenance Manual

SECTION 5 - HYDRAULICS
8. Remove cap screws from tapered bushing.
9. Insert cap screw in threaded holes in outer piece of
tapered bushing. Progressively tighten cap screw(s) until
bushing is loose on piston.
10. Remove bushing from piston.
Figure 5-6. Tapered Bushing Removal
11. Screw piston counter-clockwise and remove from rod.
12. Remove and discard piston O-rings, seal rings, and
backup rings.
13. Remove piston spacer and two wear rings from rod.
14. Remove rod from holding fixture. Remove cylinder head
and ring washer. Discard O-rings, back-up rings, rod
seals, and wiper seals.
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 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.
5-6
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 surfaces as necessary.
9. Inspect cylinder head inside diameter for scoring or
other damage. 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 surfaces as necessary.
12. Inspect cylinder head outside diameter for scoring or
other damage, ovality, and tapering. Replace as needed.
13. Inspect rod and barrel bearings for signs of 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 a correct size arbor, press bearing into steel
bushing.
NOTE: Lubrication is not required with nickel plated pins and
bearings. Install pin in composite bushing dry.
Figure 5-7. Composite Bushing Installation
14. Inspect travel limiting collar or spacer for burrs and
sharp edges. Dress inside diameter as needed. Inspect
port block fittings and holding valves. Replace as
needed. Torque holding valves to 50-55 ft-lb (68-75 Nm).
15. Inspect oil ports for blockage or presence of dirt or other
foreign material. Repair as necessary.
16. Inspect piston rings for cracks or other damage. Replace
as necessary.
– JLG Lift – 3121290