JLG 120HX ANSI Service Manual - Manual (Page 65)

SECTION 2 - PROCEDURES
3120686 – JLG Lift – 2-45
7. Place a new friction disc (12) on shaft (10) until it
contacts return plate (14).
8. Add additional new discs (11) and new friction discs
(12) as required to complete assembly.
9. Insert separators (13) in holes of return plate.
10. Install new o-ring (5), new backup ring (6), new o-
ring (8) and new back-up ring (9) on piston (7). Note
order of o-rings and back-up rings. Insert piston (7)
into end cover (2) being careful not to shear o-rings
or back-up rings.
11. Install new case seal (4) in housing (21) then install
bleeder screw (3) in end cover (2).
12. Position end cover (2) on housing (21) aligning
dowel pins (20) with holes in end cover.
NOTE: If available, a hydraulic press will simplify installation
of end cover on housing. Clamp cover in position
while tightening capscrews.
13. Press on inner ring of bearing (37) until it shoulders
on shaft (45) to eliminate binding on bearings. Be
certain to restrain opposite end of shaft to avoid
excessive thrust loading on bearing (54).
IF HYDROSTATIC BENCH TESTING IS PERFORMED ON THE
BRAKE ASSEMBLY, RELEASE PRESSURE SHOULD NOT EXCEED
2000 PSI (138 BAR) UNLESS TWO ADDITIONAL BOLTS ARE USED
FOR SUPPLEMENTAL CLAMPING.
2.21 DRIVE BRAKE
Disassembly
1. Remove end cover (13) from housing (7) by remov-
ing washer head bolts (12).
END COVER IS UNDER SPRING TENSION OF APPROXIMATELY
2,000 LB. (907 KG). THE FOUR WASHER HEAD BOLTS SHOULD
BE LOOSENED EVENLY TO RELIEVE THIS FORCE. IF A HYDRAU-
LIC PRESS IS AVAILABLE (3,000 LB. [1,360 KG MIN.]), THE
COVER CAN BE HELD IN POSITION WHILE REMOVING THE
WASHER HEAD CAP SCREWS.
2. Remove case seal (11) from housing, then remove
bleeder screw (14), o-ring (28) and gasket (29) from
end cover.
3. Remove piston (24) from end cover.
4. Remove o-ring (19), back-up ring (18), o-ring (21)
and back-up ring (20) from piston.
5. Remove separator assemblies (9, 10) from housing.
6. Remove stack assembly, consisting of discs (23),
return plate (8) and friction discs (22) from housing.
7. Remove dowel pins (17), springs (5 and 6) and
spring retainer (16) 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 (3) from housing.
9. Remove shaft (4) by pressing or using a soft mallet
on male end of shaft.
10. Remove retaining ring (15) and bearing (2) from
shaft.
11. Press rotary oil seal (1) from housing, then remove
gasket (27) and o-ring (26) from housing.
Inspection
1. Clean all parts thoroughly.
2. Closely inspect all parts for excessive wear, cracks
and chips. Replace parts as necessary.
3. Discard seals and o-rings.
4. Closely inspect bearings and bearing contact sur-
faces. Replace as necessary.
NOTE: Bearings may be re-used if, after thorough inspec-
tion, they are found to be in good condition.
Assembly
NOTE: Lubricate all seals and o-rings with clean hydraulic
oil prior to assembly.
1. Install new gasket (27) and o-ring (26) in housing
(7).
2. Press new rotary oil seal (1) into housing. Note
direction of seal.
3. Install new bearing (2) and retaining ring (15) on
shaft (4).
4. Insert shaft assembly and retaining ring (3) in hous-
ing.