JLG 3369electric, Service And Maintenance Manual

Page: 22 / 46

SECTION 2 - PROCEDURES
2-10
– JLG Sizzor– 3120768
14. With the barrel clamped securely, and while ade-
quately supporting the rod, insert the piston end into
the cylinder barrel. 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 cylinder
barrel.
16. Secure the cylinder head gland using the washer
ring and socket head bolts.
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 port block using new o-rings as
applicable.
WHEN REBUILDING THE LIFT CYLINDERS, APPLY LOCTITE 242
TO PISTON NUT AND SETSCREWS.
NOTE: These cylinders use setscrews which should be dis-
carded and replaced whenever they are removed.
19. Remove cylinder rod from the holding fixture.
20. Place new o-rings and seals in the applicable out-
side diameter grooves of both the piston and the cyl-
inder head.
21. 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.
22. With barrel clamped securely, and while adequately
supporting the rod, insert the piston end into the cyl-
inder barrel. Ensure that the piston loading o-ring
and seal ring are not damaged or dislodged.
23. 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 barrel threads.
24. If applicable, apply loctite #222 and secure the cyl-
inder head retainer using a suitable chain wrench.
NOTE: Step (16) applies to the Steer Cylinder.
25. Insert the other cylinder head gland into the barrel
cylinder. Secure the cylinder head retainer using a
suitable chain wrench.
26. After the cylinder has been reassembled, the rod
should be pushed all the way in (fully retracted) prior
to the reinstallation of any holding valves.
27. If applicable, install the cartridge type holding valve
and fittings in the rod port block using new o-rings
as applicable. Refer to Table 2-3, Holding Valve
Torque Specifications for proper torque.
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.
Table 2-2. Cylinder Piston Nut Torque Specifications
Description Nut Torque Value
(Wet)
Setscrew Torque
Value (Dry)
Lift Cylinder 400 ft. lbs.
(542 NM)
100 in. lbs.
(12 NM)
Steer Cylinder N/A N/A
Table 2-3. Holding Valve Torque Specifications
Description Torque Value
Sun - 7/8 hex M20 x1.5 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 150-160 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)