Oshkosh Corporation JLG 450AJ, Service And Maintenance Manual

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SECTION 3 - CHASSIS & TURNTABLE
3-2 – JLG Lift – 3121659
3.2 TORQUE HUB
Roll and Leak Testing
Always roll and leak test Torque-Hubs after assembly to make
sure that the unit’s gears and sealants are working properly.
The following information briefly outlines what to look for
when performing these tests.
ROLL TEST
The roll test determines if the unit’s gears rotate freely and
properly. You should be able to rotate gears by applying a
con-
stant force to the roll checker. If you feel more drag in gears
only at certain points, gears are not rolling freely. Examine
them for improper 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
consistency.
LEAK TEST
The purpose of a leak test is to make sure unit is air tight. You
can tell if your unit has a leak if pressure gauge test reading
starts to fall once you have pressurized the unit.
Leaks usually occur at the main seal or wherever O-rings or
gaskets are located. You can usually detect location of a leak
by brushing a soap and water solution around main seal and
where O-rings or gaskets meet unit exterior, then checking for
air bubbles. Replace part immediately if you detect a leak in a
seal, O-ring, or gasket.
Tightening and Torquing Bolts
USE EXTREME CARE WHEN USING AN AIR IMPACT WRENCH. DO NOT TIGHTEN
BOLTS BEYOND THEIR TORQUE SPECIFICATION. NEVER USE AN IMPACT
WRENCH TO TIGHTEN SHOULDER BOLTS. TIGHTEN ALL SHOULDER BOLTS BY
HAND.
1. Tighten (but do not torque) bolt ”A” until snug.
2. Go to opposite side of bolt circle and tighten bolt ”B”
until equally snug.
3. Continue around bolt circle and tighten remaining bolts.
4. Apply specified torque to bolt ”A”.
5. Continue around bolt circle and apply equal torque to
remaining bolts.
Figure 3-1. Bolt Tightening Sequence