JLG 680S, Service And Maintenance Manual

Page: 361 / 530

SECTION 5 - BASIC HYDRAULICS INFORMATION & SCHEMATICS
3121234 5-25
2. Use a soft mallet to tap a new wiper seal into the appli-
cable cylinder head gland groove.
3. Place a new o-ring backup ring and c-ring in the applica-
ble outside diameter groove of the cylinder head.
4. Install spanner nut onto rod. Carefully install the head
gland on the rod, ensuring that the wiper and rod seals
are not damaged or dislodged. Push the head along the
rod to the rod end, as applicable.
5. Using suitable protection, clamp the cylinder rod in a
vise or similar holding fixture as close to piston as possi-
ble.
6. Carefully thread the piston on the cylinder rod and hand
tight, ensuring that the o-ring is not damaged or dis-
lodged.
7. Install locknut onto the piston rod.
8. Remove the cylinder rod from the holding fixture.
9. Place new seals in the outer piston diameter grooves. (A
tube, with I.D. slightly larger than the O.D. of the piston
is recommended to install the solid seal).
10. 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.
11. With barrel clamped secured and adequately support-
ing 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 cylin-
der head gland can be inserted into the barrel cylinder.
13. Secure the cylinder head gland using the spanner nut
and tighten.
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.
NOTE: *Steer cylinder spanner nut is tightened as per Spec. "CYR"
Cylinder spanner nut tightening procedure. Pressurize cyl-
inder on retract to 80/100 psi to push rod guide firmly
against the round retaining ring. (Apply 1 drop of JLG
Threadlocker P/N 0100011, 2 places, at 180° apart. Hand
tighten nut, then tighten 1/4 turn with spanner wrench).
Figure 5-52. Wiper Seal Installation
CYLINDER
HEAD
RETAINER
RING
O-RING
BACKUP
SEAL
Figure 5-53. Installation of Head Seal Kit
SEAL O-RING
Figure 5-54. Installation of Piston Seal Kit