JLG 120-SXJ Service Manual - Manual (Page 77)

SECTION 5 - HYDRAULICS
3121810 – JLG Lift – 5-7
3. Carefully slide the piston spacer on the rod. If appli-
cable, align the oil holes in the rod and the spacer.
Secure the spacer, if applicable.
4. If applicable, correctly place a new o-ring and back-
up rings in the inner piston diameter groove.
5. Carefully place the piston on the cylinder rod, ensur-
ing that the o-ring and back-up rings are not dam-
aged or dislodged.
6. Using suitable protection, clamp the cylinder rod in
a vise or similar holding fixture as close to the piston
as possible.
7. Push the piston onto the rod until it abuts the spacer
end and install the attaching nut.
IF CYLINDER IS EQUIPPED WITH A PISTON NUT, APPLY “LOC-
QUIC PRIMER T” AND LOCTITE #242 TO PISTON NUT THREADS,
THEN TIGHTEN NUT TO TORQUE IN TABLE 5-1.
NOTE: Self-locking setscrews used on piston nuts should be
discarded and replaced whenever they are removed.
8. If applicable, install the setscrew(s) which secure the
piston attaching nut to the diameter groove.
9. Remove the cylinder rod from the holding fixture.
10. Place new o-rings and seals in the applicable out-
side diameter grooves of both the piston and the cyl-
inder head.
11. 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.
12. 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.
13. 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 head threads
engage the threads of the barrel.
14. If applicable, secure the cylinder head retainer using
a suitable spanner type wrench in the holes pro-
vided.
15. 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.
16. If applicable, install the cartridge-type holding valve
and fittings in the rod port block using new o-rings
as applicable.
Table 5-1. Cylinder Piston Nut Torque Specifications
Description
Nut Torque Value
(w/Loctite)
Setscrew Torque
Value (w/Loctite)
Axle Extension
Cylinder 400 ft. lb.
(542 Nm)
100 in. lb.
(11 Nm)
Jib Cylinder 400 ft. lb.
(542 Nm)
100 in. lb.
(11 Nm)
Frame Jack
Cylinder 400 ft. lb.
(542 Nm)
100 in. lb.
(11 Nm)
Level/Slave
Cylinder 200 ft. lb.
(271 Nm)
100 in. lb.
(11 Nm)
Lift Cylinder 600 ft. lb.
(813 Nm)
200 in. lb.
(22 Nm)
Master Cylinder 80 ft. lb.
(108 Nm)
100 in. lb.
(11 Nm)
Steer Cylinder 80 ft. lb.
(108 Nm)
100 in. lb.
(11 Nm)
Telescope
Cylinder 600 ft. lb.
(813 Nm)
200 in. lb.
(22 Nm)