JLG E300 Service Manual - Manual (Page 54)

SECTION 3 - CHASSIS & TURNTABLE
3-20 – JLG Lift – 3121253
3.4 DRIVE BRAKE - MICO
Disassembly
1. Remove pressure plate (3) from cover (21) by
removing the capscrews (1) and washers (2).
PRESSURE PLATE IS UNDER SPRING TENSION OF APPROXI-
MATELY 1500 LBS (680 KGF). THE FOUR CAP SCREWS SHOULD
BE LOOSENED EVENLY TO RELIEVE THIS FORCE. IF A HYDRAU-
LIC PRESS IS AVAILABLE, 3000 LBS (1361 KGF) MINIMUM, THE
PRESSURE PLATE CAN BE HELD IN POSITION WHILE REMOVING
THE CAP SCREWS AND WASHERS
2. Remove case seal (4) from cover (21).
3. Remove piston (7) from pressure plate (3).
4. Remove o-ring (5), back-up ring (6), o-ring (8) and
back-up ring (9) from piston (7).
IF THE SENSOR RING (12) IS DAMAGED OR NEEDS REPLACED,
THE ENTIRE BRAKE MUST BE REPLACED AS A UNIT. THE SEN-
SOR RING IS NOT AVAILABLE AS A SERVICE PART.
5. Remove stack assembly, consisting of stator disc
(11), sensor ring (12), rotor disc (13), and plate (14)
from cover (21).
6. Remove dowel pins (20), springs (15) and spring
retainer (16) from cover (21).
NOTE: Note number and pattern of springs for reassembly
purposes.
7. Remove retaining ring (17) from cover (21).
8. Remove shaft (10) by pressing or using a soft mallet
on male end of the shaft.
9. Remove retaining ring (19) and bearing (18) from
shaft (10).
10. Press rotary oil seal (20) from cover (18).
Assembly
NOTE: Lubricate all rubber components from the repair kit
with clean type fluid used in the system.
1. Clean all parts thoroughly before assembly.
2. Press new rotary seal (22) into cover (21). Note
direction of seal
3. Install new bearing (18) and retaining ring (19) on
shaft (10).
4. Install shaft assembly and retaining ring (17) in
cover (21).
NOTE: Be sure to use the same number of springs and
spring pattern as recorded during disassembly. This
should be five red springs evenly spaced.
5. Install dowel pins (20), spring retainer (16) and
springs (5) in cover plate (21).
6. Position plate (14) on springs (15). NOTE: Disc (13
&11) and plate (14) must remain dry during
installation. No oil residue must be allowed to
contaminate disc surfaces.
7. Place a new rotor disc (13), including speed sensor
ring (12), on the shaft (10) until it contacts the plate
(14). Install stator disc (11).
8. Install new o-ring (5), new back-up ring (6), new o-
ring (8) and new back-up ring (9) on piston (7). Note
order of o-rings and backup rings. Insert piston (7)
into pressure plate (3). Be careful not to shear o-
rings or back-up rings.
9. Install new case seal (4) in cover (21).
10. Position pressure plate (3) on cover (21) aligning
dowel pins (20) with holes in pressure plate.
NOTE: A hydraulic press will simplify installation of pressure
plate on cover. Clamp pressure plate in position
while tightening the cap screws.
11. Install capscrews (1) and washers (2) and tighten
evenly to draw pressure plate (3) to cover (21).
Torque capscrews to 55 ft.lbs. (74.6 Nm).
IF HYDROSTATIC BENCH TESTING IS PERFORMED ON THE
BRAKE ASSEMBLY, RELEASE PRESSURE SHOULD NOT EXCEED
2000 PSI (137.9 BAR) UNLESS TWO ADDITIONAL BOLTS ARE
USED FOR SUPPLEMENTAL CLAMPING.
Bleeding
1. Install brake in system and connect pressure lines.
2. Bleed pressure release section of brake by pressur-
izing side inlet port and allowing air to escape from
top port. Pressure should not exceed 100 psi (6.9
bar) during bleeding.
3. Apply sufficient pressure to release brake and check
for proper operation in system.