JLG 3246ES Service Manual - Manual (Page 41)

SECTION 3 - CHASSIS & SCISSOR ARMS
3121166 – JLG Lift – 3-5
3.4 TORQUE HUB
NOTICE
THE PROCEDURES WITHIN THIS SEC TION 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 disen-
gage procedures outlined in this section.
CAUTION
RETURN BRAKE RELEASE CABLE BEFORE RETURNING TO NOR-
MAL OPERATION.
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
equalize. 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 gasket, the part must be replaced,
and the unit rechecked. Leak test at 10 psi for 20 min-
utes.
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 (80W gear oil or 20W engine 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 loca-
tion.
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).