JLG 110HX Service Manual - Manual (Page 91)

SECTION 2 - PROCEDURES
3120864 – JLG Lift – 2-67
operator. Remove o-rings (15 and 17) and back-up
rings (14 and 16) from piston OD and ID grooves.
8. Pressure relief valve (22) can be removed and
inspected to assure spring-loaded ball moves freely
and is free of contaminants.
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 reused if, after thorough inspection,
they are found to be in good condition.
Assembly
NOTE: Lubricate all seals and o-rings with clean hydraulic
oil prior to assembly.
1. Cylinder of the power plate, piston and o-rings must
be clean prior to assembly, and pre-lubed with sys-
tem hydraulic fluid.
2. Assemble piston (13) into power plate (20) using a
shop press, being careful not to damage o-rings or
teflon back-up rings. Visually align center of cutouts
in piston (13) with torque pin (8) holes in power plate
(20).
NOTE: Avoid pushing the piston all the way to the bottom of
the cylinder in the power plate. Generally, try to keep
the top surface of the piston flush to 3.2 mm below
the machined surface of the power plate.
3. When pressing bearing onto shaft, press on inner
race of bearing and support shaft properly.
4. Rotating discs must be clean and dry. There should
be no presence of oil on any lining material or mat-
ing surfaces of the stationary discs. Worn or heavily
scored rotating discs must be replaced.
5. Press bearing (3) into housing 1. Bearing must be
seated against shoulder in housing.
6. Before installing seal (4), lubricate lip of seal with
system hydraulic fluid. Use a shop press to install
seal. Face lip of seal toward outside of brake in
order to keep gear box oil or other external contami-
nants out of brake.
7. Install seal (4) into housing by pressing evenly
around OD of seal. Use care to avoid cocking. Back
of seal must be installed flush to surface of housing.
8. Install shaft (7) into housing. Support inner race of
bearing (3) when pressing shaft into bearing.
9. Install gasket 2. Be sure to properly align. After
installing all remaining internal components of
brake, install bearing (18). Properly support shaft
when pressing bearing onto shaft.
10. Install power plate sub-assembly. Use a shop press
to evenly lower plate into position. There should be
no gap at OD when power plate is properly seated
against housing. If a shop press is not available, use
assembly bolts (21). Tighten sequentially, one turn
at a time, until power plate is properly seated.
Torque to 68-81 Nm.
11. If replacement of pressure relief valve (22) is neces-
sary, install 1/2 to 3/4 turns beyond finger tight.
12. Install in place between motor and torque hub. After
connecting hydraulic line to brake, bleed air from
brake via bleeder screw.
2.25 DRIVE BRAKE - MICO - MACHINES
BUILT MARCH 1992 TO S/N 33476
Disassembly
1. Separate end cover (2) from housing (21) by remov-
ing capscrews (1).
END COVER IS UNDER SPRING TENSION OF APPROXIMATELY
907 KG. THE FOUR BOLTS SHOULD BE LOOSENED EVENLY TO
RELIEVE THIS FORCE. IF A HYDRAULIC PRESS IS AVAILABLE
(1,360 KG MINIMUM), THE COVER CAN BE HELD IN POSITION
WHILE REMOVING THE CAPSCREWS AND LOCKWASHERS.
2. Remove case seal (4) from the housing (21), then
remove bleeder screw (3) from the end cover (2).
3. Remove piston (7) from end cover (2).
4. Remove o-ring (5), back-up ring (6), o-ring (8) and
back-up ring (9) from piston (7).
5. Remove separators (13) from housing (21).
6. Remove stack assembly, consisting of discs (11),
return plate (14) and friction discs (12) from housing
(21).
NOTE: Not all models use the same number of springs or
spring pattern. Record this information for assembly
purposes. Spring retainer (17) was not used in ear-
lier models.
7. Remove dowel pins (20), springs (15 & 16) and
spring retainer (17) from housing (21).