JLG 4394RT Service Manual - Manual (Page 132)

SECTION 4 - HYDRAULICS
4-8 – JLG Lift – 3121133
9. Place new guide locks and seals in the applicable
outside diameter grooves of the cylinder piston.
(See Figure 4-11.)
10. Position the cylinder barrel in a suitable holding fix-
ture.
NOTICE
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.
11. 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.
12. Continue pushing the rod into the barrel until the cyl-
inder head gland can be inserted into the barrel cyl-
inder.
13. Secure the cylinder head gland using the washer
ring and socket head bolts.
14. 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.
15. If applicable, install the cartridge-type holding valve
and fittings in the rod port block, using new o-rings
as applicable. (See Table 4-2, Holding Valve Torque
Specifications).
16. Push the piston onto the rod until it abuts the spacer
end and install the attaching nut.
WHEN REBUILDING THE CYLINDERS, APPLY LOCTITE #242 TO
PISTON NUT AND SETSCREW, THEN TORQUE PISTON NUT.
REFER TO TABLE 4-1, CYLINDER PISTON NUT TORQUE SPECIFI-
CATIONS
NOTE: The Steer Cylinder uses snap rings to secure piston.
17. Prior to setscrew installation spot drill rod before
installing the setscrew(s) which secure the piston
attaching nut to the diameter groove.
18. Remove the cylinder rod from the holding fixture.
19. Position the cylinder barrel in a suitable holding fix-
ture.
NOTICE
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.
Figure 4-14. Rod Assembly Installation
Table 4-1. Cylinder Piston Nut Torque Specifications
Description
Nut Torque
Value
Setscrew
torque Value
Lift Cylinder
400 ft lb
(542 Nm)
100 in lb
(12 Nm)
Lockout Cylinder N/A N/A
Steer Cylinder N/A N/A
Table 4-2. Holding Valve Torque Specifications
Description Torque Value
Sun - 7/8 hex M20 x 1.5 thds 30 - 35 ft lb 41 - 48 Nm
Sun - 1-1/8 hex 1 - 14 UNS thds 45 - 50 ft lb 61 - 68 Nm
Sun - 1-1/4 hex M36 x 2 thds 150 - 153 ft lb 204 - 207 Nm
Racine - 1-1/8 hex 1-1/16 - 12 thds 50 - 55 ft lb 68 - 75 Nm
Racine - 1-3/8 hex 1-3/16 - 12 thds 75 - 80 ft lb 102 - 109 Nm
Racine - 1-7/8 hex 1-5/8 - 12 thds 100 - 110 ft lb 136 - 149 Nm