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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2. Use a soft mallet to tap a new wiper seal into the appli-
cable cylinder head gland groove. Install new wear rings
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 washer ring onto rod, carefully install the head
gland onto the rod, ensuring that the wiper and rod seal
are not damaged or dislodged. Push the head along the
rod to the rod end, as applicable.
5. Place new o-rings in the inner piston spacer diameter
groove.
6. Carefully slide the spacer onto the rod, ensuring that the
o-rings are not damaged and dislodged.
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 hand
tight, ensuring that the o-ring and backup rings are not
damaged or dislodged.
10. Thread piston onto rod until it abuts the spacer end and
install the tapered bushing.
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 9 ft. lbs. (12.2 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. 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 5-119. Wiper Seal Installation
Figure 5-120. Installation of Head Seal Kit
TAPERED
BUSHING
ROD
CAPSCREW
PISTON
Figure 5-121. Tapered Bushing Installation
PISTON
BRASS SHAFT
ROD
CAPSCREW
TAPERED
BUSHING
Figure 5-122. Seating the Tapered Bearing