JLG 1100S Service Manual - Manual (Page 81)

SECTION 3 - CHASSIS & TURNTABLE
3121256 – JLG Lift – 3-39
3.12 SWING DRIVE
Roll and Leak Testing
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.
NOTE: The brake must be released before performing the
roll test. This can be accomplished by either pres-
sure testing using the Brake Leak Test procedure
below or by tightening the 12 bolts into the piston
through the end plate (See Brake Disassembly Pro-
cedure)
NOTE: Bolts must be removed while performing brake
release test
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 gears in your unit by applying 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
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 (MAIN UNIT)
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 air checker 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 or gaskets are located. The exact loca-
tion 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 (0.7 bar) for 20 minutes.
Tightening and Torquing Bolts
If an air impact wrench is used to tighten bolts, extreme
care should be taken to ensure that the bolts are not tight-
ened beyond their specified torque.
The following steps describe how to tighten and torque
bolts or socket head cap screws in a bolt circle.
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. Crisscross around the bolt circle and tighten remain-
ing bolts.
4. Now use a torque wrench to apply the specified
torque to bolt "A".
5. Using the same sequence, crisscross around the
bolt circle and apply an equal torque to the remain-
ing bolts.