JLG 680S Service Manual - Manual (Page 247)

SECTION 5 - HYDRAULICS
3121234 – JLG Lift – 5-7
11. Remove the cylinder rod from the holding fixture.
12. Place new guide locks and seals in the applicable
outside diameter grooves of the cylinder piston.
(See Figure 2-28. Piston Seal Kit Installation.)
13. 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.
14. 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.
15. Continue pushing the rod into the barrel until the cyl-
inder head gland can be inserted into the barrel cyl-
inder.
16. Secure the cylinder head gland using the washer
ring and socket head bolts. (See Table 2-1 and 2-3.
Torque Specifications.)
17. 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.
18. If applicable, install the cartridge-type holding valve
and fittings in the rod port block, using new o-rings
as applicable. (See Table 2-2. Holding Valve Torque
Specifications).
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, FORK-LIFT, OR OTHER
MEANS TO SUPPORT THE OVERHANGING WEIGHT OF THE
EXTENDING ROD.
Figure 5-12. Rod Assembly Installation
Table 5-1. Cylinder Head and Tapered Bushing Torque
Specifications
Description
Head Torque
Value (Wet)
Tapered Bushing
Torque Value
(Wet)
Lift Cylinder 420 ft. lbs.
(569 Nm)
45 ft. lbs.
(61 Nm)
Telescope Cylinder 80 ft. lbs.
(108 Nm
9 ft. lbs.
(12.2 Nm)
Level Cylinder 80 ft. lbs.
(108 Nm)
9 ft. lbs.
(12.2 Nm)
Lockout Cylinder 80 ft.lbs.
(108 Nm)
9 ft. lbs.
(12.2 Nm)
Table 5-2. Holding Valve Torque Specifications
Description Torque Value
SUN - 7/8 HEX M20 X 1.5 THDS. 30-35 ft. lbs.
(41-48 Nm)
SUN - 1 1/8 HEX 1 -14 UNS THDS. 45-50 ft. lbs.
(61-68 Nm)
SUN - 1 1/4 HEX M36 X 2 THDS. 150-160 ft. lbs.
(204-217 Nm)
RACINE - 1 1/8 HEX 1 1/16 - 12 THDS. 50-55 ft. lbs.
(68-75 Nm)
RACINE - 1 3/8 HEX 1 3/16 - 12 THDS. 75-80 ft. lbs.
(102-109 Nm)
RACINE - 1 7/8 HEX 1 5/8 - 12 THDS. 100-110 ft. lbs.
(136-149 Nm)