JLG 1850SJ Service Manual - Manual (Page 184)

SECTION 5 - BASIC HYDRAULIC INFORMATION & HYDRAULIC SCHEMATICS
5-14 – JLG Lift – 3121619
9. Loosen and remove bolts from tapered bushing and pis-
ton.
10. Insert bolts in threaded holes in outer piece of tapered
bushing. Progressively tighten bolts until bushing is
loose. Remove tapered bushing from piston.
11. By hand, screw the piston counterclockwise and remove
it from cylinder rod.
REMOVE SEALS USING A BRASS OR PLASTIC PICK ONLY. DO NOT USE A KNIFE,
SHARP OBJECT, OR SCREW DRIVER. MAKE NOTE OF SEAL ORIENTATION
BEFORE REMOVING FOR PROPER INSTALLATION.
12. Remove and discard backup ring, o-ring, and backup
ring from inside grooves of piston. Remove and discard
two lock rings and seals from outer grooves of piston.
13. Remove piston spacer from rod.
14. Remove rod from holding fixture. Remove cylinder head
and washer ring.
15. Remove and discard two wear rings, wiper seal, and rod
seal from inside of cylinder head. Remove and discard O-
ring and backup ring from outer groves of cylinder head.
CLEANING AND INSPECTION
1. Clean parts thoroughly with 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 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, scoring, or 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 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,
damage, ovality, and tapering. Replace as necessary.
13. 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.
NOTE: Lubrication is not required with nickel plated pins and
bearings. Install pin in composite bushing dry.
Rod
Piston
Tapered
Bushing
Rod
Bolt
Figure 5-14. Tapered Bushing Removal