JLG 80HX_HX+6_HXER Service Manual - Manual (Page 40)

SECTION 2 - PROCEDURES
2-18 – JLG Lift – 3120863
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 into the
barrel cylinder. Ensure that the piston loading o-ring
and seal ring are not damaged or dislodged.
14. Place the support rods in the tubes provided on the
barrel assembly. The rods will bottom out on the
attached stops. Thread the rods through the rod
support block and, using loctite, tighten the rod nuts
down on the support.
THE SUPPORT RODS MUST BE INSTALLED SO THAT THEY BOT-
TOM OUT SIMULTANEOUSLY ON THE STOPS.
15. Continue pushing the rod into the barrel until the cyl-
inder head gland can be inserted into the barrel cyl-
inder or, if applicable, until the cylinder threads
engage the threads of the barrel.
16. If applicable, secure the cylinder head gland using a
suitable spanner type wrench in the holes provided.
17. If applicable, secure the cylinder head retainer using
a suitable spanner type wrench in the holes pro-
vided.
18. 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.
19. If applicable, install the cartridge-type holding valve
and fittings in the rod port block using new o-rings
as applicable. (See Table 2-3, Holding Valve Torque
Specification).
IF THE CYLINDER IS TO BE TESTED PRIOR TO INSTALLATION ON
THE MACHINE, EXTREME CARE SHOULD BE USED TO INSURE
THAT THE OUTER END OF THE ROD IS SUPPORTED. USE
EITHER A TRAVELING OVERHEAD HOIST, FORKLIFT, OR OTHER
MEANS TO SUPPORT THE OVERHANGING WEIGHT OF THE
EXTENDING ROD.
NOTE: Steps 20 thru 23 apply to the Boom Telescope Cylin-
ders.
20. Elevate the barrel end of the cylinder to a work
bench or other suitable device.
21. Plug the retract port and supply hydraulic power to
the extend port.
22. Open the bleeder port plug (TP) venting all trapped
air to atmosphere. Retighten the bleeder port plug.
Disconnect the hydraulic power source and remove
plug from retract port.
23. An alternative to steps (20) through (23) is to posi-
tion the barrel horizontally in a suitable holding
device, attach a hydraulic power source to both
extend and retract ports, while supporting the cylin-
der rod, cycle the cylinder a minimum of 5 times with
the bleeder port unplugged venting all trapped air to
atmosphere. A suitable hose may be attached to the
bleeder port with the end in a container suitable to
contain the hydraulic fluid. After all air is vented
remove all attached hoses, and install the bleeder
port plug. Also plug the extend and retract ports until
cylinder is installed in boom.