JLG 600SJ Service And Maintenance Manual page 204

SECTION 4 - BOOM & PLATFORM
Each T-seal has 2 back-up rings (see drawing for ori-
entation).
Beginning with the inner seal (200) insert one end of
b/u ring in the lower groove and feed the rest in
using a circular motion. Make sure the wedged ends
overlap correctly.
Repeat this step for the outer seal (202).
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7. Insert the piston (3) into the housing (1) as shown,
until the outer piston seal (202) is touching inside
the housing bore.
8. Looking from the angle shown, rotate the piston (3)
until the marks you put on the piston and the hous-
ing (1) during disassembly line up as shown. Using
a rubber mallet, tap the piston into the housing up to
the point where the gear teeth meet.
– JLG Lift – 3121202