JLG 2658E3 Service Manual - Manual (Page 25)

SECTION 2 - PROCEDURES
3120878 – JLG Lift – 2-13
10. Remove the cylinder rod from the holding fixture.
11. Install new seals and a new guidelock ring in the
applicable outside diameter grooves of the piston.
12. Position the cylinder barrel in a suitable holding fix-
ture.
EXTREME CARE SHOULD BE TAKEN WHEN INSTALLING THE
CYLINDER ROD, HEAD, AND PISTON. AVOID PULLING THE ROD
OFF-CENTER, WHICH COULD CAUSE DAMAGE TO THE PISTON
AND CYLINDER BARREL SURFACES.
13. With barrel clamped securely, and while adequately
supporting the rod, insert the piston end of the rod
into the cylinder barrel. Ensure that the piston seals
are not damaged or dislodged.
14. Continue pushing the rod into the barrel until the cyl-
inder head can be inserted into the cylinder barrel.
15. Slide the head into the barrel and engage the
threads. Turn the head counterclockwise until the
first thread just passes the engagement point (the
head will move noticeably), then turn the head
clockwise until it is hand-tight or fully seated. Insert a
spanner wrench into the holes provided and tighten
1/8 to 1/4 turn past fully seated.
16. After the cylinder has been reassembled, the rod
should be pushed all the way in (fully retracted) prior
to the reinstallation of any holding valve or valves.
17. If removed, install the cartridge-type holding valve
and fittings in the port block using new o-rings as
applicable. Torque the holding valve cartridge to 68-
75 Nm (50-55 ft lb).
2.13 BRAKE CYLINDER REPAIR
Disassembly
DISASSEMBLY OF THE CYLINDER SHOULD BE PERFORMED ON
A CLEAN WORK SURFACE IN A DIRT FREE WORK AREA.
1. Tag and disconnect the hoses from the cylinder
ports.
DO NOT FU LLY EXTEN D CYLINDER TO END OF STROKE.
RETRACT CYLINDER SLIGHTLY TO AVOID TRAPPING PRES-
SURE.
2. Place the cylinder barrel into a suitable holding fix-
ture.
3. Using a suitable pair of snap ring pliers, carefully
remove the retaining ring from the cylinder barrel.
4. Attach a suitable pulling device to the cylinder rod
end.
EXTREME CARE SHOULD BE TAKEN WHEN REMOVING THE CYL-
INDER ROD, GUIDE, AND PISTON. AVOID PULLING THE ROD
OFF-CENTER, WHICH COULD CAUSE DAMAGE TO THE PISTON
AND CYLINDER BARREL SURFACES.
5. With the barrel clamped securely, apply pressure to
the rod pulling device and carefully withdraw the
complete rod assembly from the cylinder barrel.
6. Using suitable protection, clamp the cylinder rod in
a vise or similar holding fixture.
7. Carefully remove the piston locknut and piston from
the cylinder rod. Remove and discard the piston ring
and o-rings.
8. Carefully remove the guide from the cylinder rod.
Remove and discard the o-ring, back-up ring, rod
seal, and wiper ring.
9. Remove the cylinder rod from the holding fixture.
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 dam-
age. Dress threads as necessary.
4. Inspect inner surface of cylinder barrel tube for scor-
ing 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 necessary.
6. Inspect seal and o-ring grooves in piston for burrs
and sharp edges. Dress applicable surfaces as nec-
essary.
7. Inspect cylinder guide inside diameter for scoring or
other damage and for ovality and tapering. Replace
as necessary.
8. Inspect seal and o-ring grooves in guide for burrs
and sharp edges. Dress applicable surfaces as nec-
essary.