JLG 3248RS/10RS Service Manual - Manual (Page 58)

SECTION 3 - CHASSIS & SCISSOR ARMS
3-26 – JLG Lift – 3121273
3.14 TORQUE HUB SERVICING
NOTICE
THE PROCEDURES WITHIN THIS SECTION APPLY TO ALL
MACHINES AND TORQUE HUBS. PROCEDURES THAT APPLY TO
SPECIFIC MACHINES AND TORQUE HUBS WILL BE SO NOTED
BY PROPER SERIAL NUMBERS.
NOTE: These instructions will cover how to completely
assemble and disassemble the Torque-Hub unit.
However, if the unit is under warranty you should
contact JLG Industries, Inc. for a replacement unit.
The warranty will no longer be valid if the unit is dis-
assembled by non-JLG personnel.
NOTICE
TORQUE HUB UNITS SHOULD ALWAYS BE ROLL AND LEAK
TESTED BEFORE DISASSEMBLY AND AFTER ASSEMBLY TO
MAKE SURE THAT THE UNIT’S GEARS AND SEALANTS ARE
WORKING PROPERLY.
Torque-Hub units should always be roll and leak tested
before disassembly and after assembly to make sure that
the unit's gears, bearings and seals are working properly.
The following information briefly outlines what to look for
when performing these tests.
IF THE MACHINE IS ON ANY INCLINE, THE WHEELS MUST BE
ADEQUATELY BLOCKED PRIOR TO MANUALLY DISENGAGING
THE BRAKES. FAILURE TO DO SO MAY RESULT IN INJURY OR
EVEN DEATH.
NOTE: The brake must be released before performing the
roll test. This can be accomplished by connecting the
brake release cable and depressing button. The
brake can also be released by following the manual
disengage procedures outlined in this section.
CAUTION
RE-ENGAGE BRAKES BEFORE RETURNING TO NORMAL OPER-
ATION.
Roll Test
The purpose of the roll test is to determine if the unit's
gears are rotating freely and properly. You should be able
to rotate the wheel or hub of the gearbox by hand. If you
feel more drag in the gears only at certain points, then the
gears are not rolling freely and should be examined for
improper installation or defects. Some gear packages roll
with more difficulty than others. Do not be concerned if the
gears in your unit seem to roll hard as long as they roll
with consistency.
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 reading on your leak checking fitting starts to fall
after the unit has been pressurized and allowed to equal-
ize. Leaks will most likely occur at the pipe plugs, the main
seal or wherever o-rings 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 the o-rings
or gaskets meet on the exterior of the unit, then checking
for air bubbles. If a leak is detected in a seal, o-ring or gas-
ket, the part must be replaced, and the unit rechecked.
Leak test at 10 psi for 20 minutes.
NOTE: Due to the small air volume inside this Torque-Hub, it
will pressurize to 10 psi very quickly. If the pressure
becomes excessive in the unit the seals will be
destroyed.
Oil Check/Fill Procedure
The torque hub unit is shipped with ISO 68 viscosity oil
(hydraulic fluid). It is designed to utilize the same oil
throughout its service life. However, should it need to be
checked/serviced use the following procedure.
In the event of servicing, fill the unit with ISO grade 68
hydraulic oil.
NOTE: The gearbox capacity is 10 oz of oil.
1. To check the oil level, rotate the wheel so that the
plugs in the cover are at 12 o-clock and 3 o-clock.
2. Allow the oil to settle than slowly remove the plug at
3 o-clock.
3. If oil begins to come out the oil level is sufficient.
4. If no oil is noticed at the 3 o-clock plug remove both
plugs.
5. Slowly add oil at the 12 o-clock plug location until oil
begins to seep out at the 3 o-clock plug location.
6. Apply pipe dope or teflon tape to the cover plugs
and reinstall into the cover.
7. TIghten to 6 ft lbs - 8 ft lbs (8.4 Nm to 11.2 Nm).