JLG 680S, Service And Maintenance Manual

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SECTION 5 - BASIC HYDRAULICS INFORMATION & SCHEMATICS
3121234 5-13
2. Use a soft mallet to tap a new wiper seal into the appli-
cable cylinder head gland groove. Install a new wear
ring into the applicable cylinder head gland groove.
3. Place a new o-ring and backup ring in the applicable
outside diameter groove of the cylinder head.
4. 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 onto the rod.
NOTE: Apply JLG Threadlocker P/N 0100011 on threads of set-
screw before installation.
6. Install setscrew onto the spacer.
7. Using suitable protection, clamp the cylinder rod in a
vise or similar holding fixture as close to piston as possi-
ble.
8. Place a new o-ring and backup rings in the inner piston
diameter groove.
9. Carefully thread the piston on the cylinder rod and hand
tight, ensuring that the o-ring and backup rings are not
damaged or dislodged.
10. Insert the tapered bushing into piston.
NOTE: When installing the tapered bushing, piston and mating
end of rod must be free of oil.
11. Assemble the tapered bushing loosely into the piston
and insert capscrews through the drilled holes in the
bushing and into the tapped holes in the piston.
12. Tighten the capscrews evenly and progressively in rota-
tion to 30 ft. lbs. (41 Nm).
13. After the screws have been torqued, tap the tapered
bushing with a hammer (16 to 24 oz.) and brass shaft
(approximately 3/4 in. diameter) as follows:
a. Place the shaft against the cylinder rod and in con-
tact with the bushing in the spaces between the
capscrews.
b. Tap each space once; this means the tapered bush-
ing is tapped 3 times as there are 3 spaces between
the capscrews.
Figure 5-23. Wiper Seal Installation
Figure 5-24. Installation of Head Seal Kit
TAPERED
BUSHING
ROD
CAPSCREW
PISTON
Figure 5-25. Tapered Bushing Installation
PISTON
BRASS SHAFT
ROD
CAPSCREW
TAPERED
BUSHING
Figure 5-26. Seating the Tapered Bearing