JLG 680S, Service And Maintenance Manual

Page: 350 / 530

SECTION 5 - BASIC HYDRAULICS INFORMATION & SCHEMATICS
5-14 3121234
14. Rotate the capscrews evenly and progressively in rota-
tion to 30 ft. lbs. (41 Nm).
15. 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.
16. 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).
17. 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.
18. With barrel clamped secured and adequately support-
ing the rod, insert the piston end into the barrel cylinder.
Ensure that the piston loading hydrolock seals and
guidelock rings are not damaged or dislodged.
19. Continue pushing the rod into the barrel until the cylin-
der head gland can be inserted into the barrel cylinder.
20. Apply JLG Threadlocker P/N 0100011 to the socket head
bolts and secure the cylinder head gland using the cap-
screws. Torque capscrews to 300 ft. lbs. (407 Nm).
21. After the cylinder has been reassembled, the rod should
be pushed all the way in (fully retracted) prior to the re-
installation of any holding valve or valves.
22. Install the relief valve before installing the plug. Torque
the relief valve to 5 ft. lbs. (7 Nm). Install the remaining
plugs, using new o-rings as applicable.
Figure 5-27. Hydrolock Piston Seal Installation
Figure 5-28. Piston Seal Kit Installation
GUIDELOCK
RING
HYDROLOCK
SEAL
O-RING
BACKUP RING
Figure 5-29. Rod Assembly Installation
BARREL
PISTON
ROD
HEAD
WASHER RING
CAPSCREW
ROD