JLG 740AJ, Service And Maintenance Manual

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SECTION 5 - BASIC HYDRAULIC INFOR M ATION AND SCHE M ATICS
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13. Rotate the capscrews evenly and progressively in rota-
tion to 9 ft. lbs. (12.2 Nm).
14. Remove the cylinder rod from the holding fixture.
WHEN INSTALLING HYDROLOCK PISTON SEALS, ENSURE SEALS ARE
INSTALLED PROPERLY. REFER TO HYDROLOCK PISTON SEAL INSTALLATION
FOR CORRECT SEAL ORIENTATION. IMPROPER SEAL INSTALLATION COULD
RESULT IN CYLINDER LEAKAGE AND IMPROPER CYLINDER OPERATION.
15. Place new hydrolock seals and guidelock rings in the
outer piston diameter groove. (A tube, with I.D. slightly
larger than the O.D. of the piston is recommended to
install the solid seal).
16. Position the cylinder barrel in a suitable holding fixture.
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.
17. With barrel clamped securely, and while adequately sup-
porting the rod, insert the piston end into the barrel cyl-
inder. Ensure that the piston loading hydrolock seals and
guidelock rings are not damaged or dislodged.
18. Continue pushing the rod into the barrel until the cylin-
der head gland can be inserted into the barrel cylinder.
19. Apply JLG Threadlocker (P/N 0100011) to the socket
head bolts and secure the cylinder head gland using the
washer ring and bolts. Torque bolts to 35 ft. lbs.
(47.5 Nm).
20. 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.
21. Install the counterbalance valves and fittings in the rod
port block, using new o-rings as applicable. Torque to
counterbalance valves as shown in Figure 5-79., Slave
Cylinder.
Figure 5-88. Hydrolock Piston Seal Installation
Figure 5-89. Piston Seal Kit Installation
HYDROLOCK
SEAL
GUIDELOCK
RING
O-RING
BACKUP
RING
BARREL
PISTON
ROD
HEAD
SPACER
WASHER RING
CA
1
SCREW
ROD
Figure 5-90. Rod Assembly Installation