JLG 24RS Service Manual - Manual (Page 69)

SECTION 3 - CHASSIS & TURNTABLE
3121287 – JLG Lift – 3-31
BREAK LEAK REPAIR PROCEDURE
Install two flat socket head capscrews 0.250-20 UNC, ½" length
into holes in brake piston evenly. tighten bolts in steps evenly
to ensure that the pressure plate (8M) does not get wedged
into brake cylinder.
Carefully remove retaining ring from brake housing. Remove
the brake piston from brake housing.
Check o-rings, backup rings, and brake cavity in brake housing
for damage. If no damage is found, then reinstall input brake
according to input brake installation procedure under main
assembly procedure and perform pressure test again. If brake
still leaks, contact JLG.
NOTE: Failure to perform this test may result in damaged or inef-
fective brake parts.
Roll and Leak Test
Torque-Hubs should always be roll and leak tested before dis-
assembly (if possible) and after assembly to make sure the
unit’s gears, bearings, and seals are working properly. The fol-
lowing information briefly outlines what to look for when per-
forming these tests.
The Roll Test:
The purpose of the roll test is to determine if the unit’s gears
are rotating consistently, easily and properly. Remove Motor
and release the brake by applying 400 psi to the brake port. To
perform a roll test, use the recommended tool shown below
(or something equivalent) to apply constant rotational force to
the input of the gearbox. If more drag is felt in the gears only
at certain points, then the gears are not rolling consistently
and easily 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 the unit seem to
roll hard as long as they roll with consistency. Rotate the gear-
box 36 revolutions both clockwise and counterclockwise.
The Leak Test:
The purpose of a leak test is to make sure the unit is airtight. To
perform a leak test use the leak test fixture from the table
below. If the tool is not available, the gearbox must be sealed
to perform the test. This can be accomplished by assembling
the sealed input device onto the gearbox at the input end and
replace one of the oil plugs with an air chuck. DO NOT EXCEED
10 PSI (0.7 BAR) PRESSURE DURING THE LEAK TEST. Higher
pressure will create a false sealing effect in assemblies with lip-
seals. The unit has a leak if the pressure gauge reading on your
leak check fitting starts to fall after the gearbox has been pres-
surized 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 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 exte-
rior of the unit and 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 min-
utes.
T201476