JLG 3246ES Service Manual - Manual (Page 114)

SECTION 4 - HYDRAULICS
4-12 – JLG Lift – 3121166
14. Screw the piston CCW, by hand, and remove the
piston from cylinder rod.
15. Remove and discard the piston o-rings, seal rings,
and backup rings.
16. If applicable, remove the piston spacer from the
rod.
17. Remove the rod from the holding fixture. Remove
the cylinder head gland and retainer plate, if appli-
cable. Discard the o-rings, back-up rings, rod seals,
and wiper seals.
Steer Cylinder Piston Removal - Cyl. p/n-
1684456
1. Using the spanner holes, rotate the piston until the
end of the retarining ring can be seen through the
cross-drilled retaining ring hole.
2. Insert a flathead screwdriver (or similar tool) into
the cross-drilled retaining ring hole.
3. Using the screwdriver, guide the retaining ring
into the cross-drilled retaining ring hole while
turning the piston.
4. Continue turning the piston approximately one (1)
full turn until the start of the retaining ring is again
aligned with the cross-drilled retaining ring hole.
5. Lift up on the retaining ring so that the hook on
the start of the retaining ring releases from the
hole in the rod.
6. Pull the retraining ring all the way out of the cross-
drilled retraining ring hole.
7. Slide the piston over the rod in the direction of the
spanner holes to remove.
Cleaning and Inspection
1. Clean all parts thoroughly in an approved cleaning
solvent.
2. Inspect the cylinder rod for scoring, tapering, oval-
ity, or other damage. If necessary, dress rod with
Scotch Brite or equivalent. Replace rod if neces-
sary.
3. Inspect threaded portion of rod for excessive dam-
age. 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 pis-
ton 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 nec-
essary.
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 nec-
essary.
12. Inspect cylinder head outside diameter for scoring
or other damage and ovality and tapering. Replace
as necessary.
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 dam-
age. If steel bushing is worn or damaged, rod/
barrel must be replaced.
c. Lubricate inside of steel bushing with WD40
prior to bearing installation.
d. Using an arbor of the correct size, carefully
press the bearing into steel bushing.
NOTE: Install pin into the Gar-Max bearing dry. Lubrication
is not required with nickel plated pins and bearings.
14. Inspect travel limiting collar or spacer for burrs and
sharp edges. If necessary, dress inside diameter
surface with Scotch Brite or equivalent.
15. If applicable, inspect port block fittings and hold-
ing valve. Replace as necessary.
16. Inspect the oil ports for blockage or the presence
of dirt or other foreign material. Repair as neces-
sary.
17. If applicable, inspect piston rings for cracks or
other damage. Replace as necessary.
STEEL
BUSHING
GAR-MAX
BUSHING
ARBOR
Figure 4-5. Gar-Max Bearing Installation