JLG 25RTS, Service & Maintenance

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SECTION 2 - PROCEDURES
2-28 – JLG Sizzor – 3120826
BEWARE OF SHARP EDGES IN COUNTER BORE WHEN REMOV-
ING O-RING.
18. Remove o-ring from counter bore in hub. Discard o-
ring.
19. If necessary, disassemble hub-spindle assembly as
follows:
NOTE: Start with large end of hub facing up, large end of
spindle facing down.
WEAR SAFETY GLASSES WHILE PERFORMING STEP (A).
a. Remove retaining ring from around spindle in
hub.
b. Remove spacer from around spindle in hub.
c. Set hub, small end/spindle facing down, up on
something that will support hub’s flange while it
lifts hub up so spindle is not resting on anything.
Carefully press or hammer spindle down out of
hub. If seal and bearing cone come out of hub
and rest on spindle, remove these parts from
spindle and set them aside. Discard seal.
d. If seal and bearing cone did not come out of
small end of hub when spindle was pressed out
of hub, remove seal and bearing cone from
small end of hub. Discard seal.
e. Bearing cone should be lying loose in wide end
of hub. Remove bearing cone from inside hub.
NOTE: If hammer and punch are used to remove bearing
cups, make sure counter bore is not struck with
punch when removing bearing cup.
f. Remove bearing cup from counter bore in small
end of hub.
g. Turn hub over and lift it out of flange-support.
Remove bearing cup from wide end of hub.
h. Press nine studs out of stud holes in hub.
Roll Test
The purpose of a roll test is to determine if the unit’s gears
are rotating freely and properly. Gears should be able to
be rotated by applying a constant force to the roll checker.
If more drag is felt in the gears only at certain points, then
the gears are not rolling freely and should be be examined
for proper installation or defects. Some gear packages roll
with more difficulty than others. Do not be concerned if
gears seem to roll hard as long as they roll with consis-
tency.
Leak Test
The purpose of the leak test is to make sure the unit is air
tight. The unit has a leak if the pressure gauge reading on
the air checker starts to fall once the unit has been pres-
surized. Leaks will most likely occur at main seal or wher-
ever o-rings or gaskets are located. The exact location of
a leak can usually be detected by brushing a soap and
water solution around the main seal and where o-rings or
gaskets meet the exterior of the unit, then checking for air
bubbles. If a leak is detected in a seal, o-ring, or gasket,
the part must be replaced.
Assembly
BEWARE OF SHARP EDGES IN COUNTER BORE WHEN INSTALL-
ING O-RING.
Assemble hub-spindle assembly as follows:
NOTE: Make sure cup sits square with counter bore before
pressing.
1. Set hub onto its large end. Press bearing cup into
counter bore in small end of hub.
2. Press nine studs into stud holes in hub.