Brake Leak Repair Procedure; Roll And Leak Test - JLG 400SC Service And Maintenance Manual

SECTION 3 - CHASSIS & TURNTABLE
Install the large retaining ring into groove in Housing making
sure that it is seated properly. Remove all bolts from the brake
piston and discard.
NOTE: Use caution when removing bolts as they are subject to
spring pressure. Make sure the retaining ring is secured
before removing bolts.
Re-test input brake. If release and/or lockup pressures still do
not match the brake chart contact JLG Service Department.
Grease and install O-ring onto motor pilot. Place motor into
brake pilot and line up holes. Check timing marks. Assemble
lift lugs onto hex bolts and assemble hex bolts with lugs
through the motor and brake against the motor flange. Torque
to 80-100 ft-lb (108-136 Nm).
Re-test input brake. If release and/or lockup pressures still do
not match the brake chart contact JLG Service Department.

Brake Leak Repair Procedure

Remove brake piston from housing using the Brake Disassem-
bly Procedure.
Check O-rings, Backup Rings, and brake cavity in Brake Hous-
ing 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 the service department.
NOTE: Failure to perform this test may result in damaged or inef-
fective brake parts.
3-10

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
gears, bearings, and seals are working properly. The following
information briefly outlines what to look for when performing
these tests.
THE ROLL TEST
The purpose of the roll test is to determine if the unit gears are
rotating consistently, easily and properly. Remove Motor and
release the brake by applying 400 psi to the brake port. To per-
form a roll test, use the recommended tool from table 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.
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