JLG 4394RT - Piston Seal Kit Installation

SECTION 4 - HYDRAULICS
3121642 – JLG Lift – 4-7
8. Using suitable protection, clamp the cylinder rod in a
vise or similar holding fixture as close to piston as possi-
ble.
9. Carefully thread the piston on the cylinder rod hand
tight, ensuring that the o-ring and back-up 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 JLG capscrews (not vendor 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 the specified torque value.
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.
14. Re-torque the capscrews evenly and progressively in
rotation to the specified torque value.
15. Remove the cylinder rod from the holding fixture.
16. Place new guide locks and seals in the applicable out-
side diameter grooves of the cylinder piston. (See Figure
4-11.)
Figure 4-11. Piston Seal Kit Installation
Figure 4-12. Tapered Bushing Installation
Figure 4-13. Seating the Tapered Bearing