SECTION 3 - CHASSIS, PLATFORM & SCISSOR ARMS
3121642 – JLG Lift – 3-5
3.3 DRIVE HUB (FAIRFIELD)
Roll and Leak Testing
Always roll and leak test Drive-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.
THE ROLL TEST
The purpose of a roll test is to determine if the unit’s gears are
rotating freely and properly. You should be able to rotate the
gears in your unit by applying a constant
force to the roll
checker. If you feel more
drag in the gears only at certain
points, then the gears are not rolling freely and you should
examine them for improper installation or defects. Some gear
packages roll with more difficulty than others. Do not be con-
cerned if the gears in your unit seem to roll hard as long as
they roll with consistency
THE LEAK TEST
The purpose of a leak test is to make sure the unit is air tight.
You can tell if your unit has a leak if the pressure gauge read-
ing on your air checker starts to fall once you have pressurized
the unit. Leaks will most likely occur at the main seal or wher-
ever o-rings or gaskets are located. Usually you can detect the
exact location of a leak 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 you detect
a leak in a seal, o-ring, or gasket, replace the part immediately.
Tightening and Torquing Bolts
If you use an air impact wrench to tighten bolts, take extreme
care to ensure that you do NOT tighten the bolts beyond their
indicated torque specification. Never
use an impact wrench to
tighten shoulder bolts. Always
tighten all shoulder bolts by
hand.
The following steps describe the proper procedure for tighten-
ing and torquing bolts or socket head cap screws in a bolt cir-
cle.
1. Tighten (but do not torque) bolt ”A” until snug.
2. Go to the opposite side of the bolt circle and tighten
bolt ”B” until equally snug.
3. Continue around the bolt circle and tighten the remain-
ing bolts.
4. Now use a torque wrench to apply the specified torque
to bolt ”A”.
5. Continue around the bolt circle and apply an equal
torque to the remaining bolts.
Oil Information
1. TYPE – EP90
On normal applications, use EP90. On applications
where the lubricant must meet special requirements,
the O.E.M. should be able to recommend a suitable sub-
stitute.
2. OIL TEMPERATURE
Continuous – 160°F [70°C] Intermittent – 200°F [95°C]
3. OIL CHANGE
Initial – After 50 hours or 50,000 revolutions of opera-
tion. Subsequent – After 1000 hours or (1) year, which-
ever comes first.
NOTE: Higher temperatures make it necessary to change oil more
frequently.
4. OIL FILL LEVEL AND VOLUME
Unit mounted horizontal – half full
Approximate volume - 17 oz. (0.5 ltr)
5. REAR BRAKES
Rear brakes require 2.7 oz. (0.08 ltr) of DTE 13M hydraulic
fluid each to function properly.
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