JLG 500RTS ANSI Service Manual - Manual (Page 42)

SECTION 2 - PROCEDURES
2-26 – JLG Sizzor – 3120696
2.23 DRIVE BRAKE - 2WD/4WD REAR
Disassembly
1. Remove end cover from housing by removing
washer head cap screws.
END COVER IS UNDER SPRING TENSION OF APPROXIMATELY
2000 LBS. (907 KG). THE FOUR WASHER HEAD CAP SCREWS
SHOULD BE LOOSENED EVENLY TO RELIEVE THIS FORCE. IF A
HYDRAULIC PRESS IS AVAILABLE (3000 LBS. MIN.) (1361 KG
MINIMUM), COVER CAN BE HELD IN POSITION WHILE REMOVING
WASHER HEAD CAP SCREWS.
2. Remove case seal from housing, then remove
bleeder screw from end cover.
3. Remove piston from end cover.
4. Remove o-ring, back-up ring, o-ring and back-up
ring from piston.
5. Remove separators from housing.
6. Remove stack assembly, consisting of stator friction
discs, return plate, and rotor discs from housing.
7. Remove dowel pins, springs, and spring retainer
from housing.
NOTE: Not all models use the same number of springs or
spring pattern. Record this information for assembly
purposes.
8. Remove retaining ring from housing.
9. Remove shaft by pressing or using a soft mallet on
male end of shaft.
10. Remove retaining ring and bearing from shaft.
11. Press rotary oil seal from housing.
Assembly
NOTE: Lubricate all rubber components from repair kit with
clean hydraulic fluid of the type used in the system.
1. Clean all parts thoroughly before assembly.
2. Press new rotary oil seal into housing. Note direction
of seal.
3. Install new bearing and retaining ring on shaft.
4. Insert shaft assembly and retaining ring in housing.
5. Insert dowel pins, guide retainer, and springs in
housing.
NOTE: Be sure to use the same number of springs and
same spring pattern as recorded during disassem-
bly.
6. Position new large diameter return plate in housing
with tabs guided by dowel pins until disc rests on
springs.
NOTE: Rotor discs and stator friction discs should remain
dry during installation. No oil residue should be
allowed to contaminate disc surfaces.
7. Place a new rotor disc on shaft until it contacts
return plate.
8. Add additional new stator discs and new rotor discs
as required to complete assembly.
9. Insert separators in holes of return plate.
10. Install new o-ring, new back-up ring, new o-ring, and
new back-up ring on piston. Note order of o-rings
and back-up rings. Insert piston into end cover,
being careful not to shear o-rings or back-up rings.
11. Install case seal in housing, then install bleeder
screw in end cover.
12. Position end cover on housing, aligning dowel pins
with holes in end cover.
13. Install washer head cap screws and tighten evenly
to draw end cover to housing. Torque washer head
cap screws to 55 ft lbs (75 Nm).
NOTE: If available, a hydraulic press will simplify installation
of end cover on housing. Clamp cover in position
while tightening washer head cap screws.
14. If hydrostatic bench testing is done on brake assem-
bly, release pressure should not exceed 2000 psi
(138 bar) unless two additional bolts are used for
supplemental clamping.