JLG 680S Service Manual - Manual (Page 246)

SECTION 5 - HYDRAULICS
5-6 – JLG Lift – 3121234
wear ring into the applicable cylinder head gland
groove.
3. Place a new “o”ring and back-up seal in the applica-
ble outside diameter groove of the cylinder head.
4. Install washer ring 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. Carefully slide the piston spacer on the rod.
NOTE: Upper telescope cylinder piston has an o-ring
installed inside the spacer.
6. If applicable, correctly place a new o-ring and back-
up rings in the inner piston diameter groove.
7. Using suitable protection, clamp the cylinder rod in
a vise or similar holding fixture as close to piston as
possible.
8. Carefully thread the piston on the cylinder rod hand
tight, ensuring that the o-ring and back-up rings are
not damaged or dislodged.
9. Thread piston onto rod until it abuts the spacer end
and install the tapered bushing.
NOTE: When installing the tapered bushing, piston and mat-
ing end of rod must be free of oil.
WHEN REBUILDING THE MASTER, SLAVE, LIFT, AXLE LOCKOUT,
OR TELESCOPE CYLINDERS, APPLY LOCTITE #242 TO TAPERED
BUSHING BOLTS, THEN TIGHTEN SECURELY. (SEE TABLE 2-1
AND 2-3. TORQUE SPECIFICATIONS).
10. Install the bolts in tapered bushing using loctite
#242. (See Table 2-1 and 2-3. Torque Specifica-
tions.)
Figure 5-7. Poly-Pak Piston Seal Installation
Figure 5-8. Wiper Seal Installation
Figure 5-9. Installation of Head Seal Kit
Figure 5-10. Piston Seal Kit Installation
Figure 5-11. Tapered Bushing Installation