SERVICE REPAIR
R30CH [A186]
1
INTRODUCTION
GENERAL
This section has the description, repair and adjustment
procedures for the brake assemblies. A troubleshooting
table is at the end of the section.
DESCRIPTION
(See FIGURE 1. and FIGURE 2.)
There is a brake assembly on each drive unit of the
R40BH and R40EH trucks, or at the top of the master
drive unit of the TWR and Tractor vehicles. These as-
semblies are disc brakes that have brake lining material
on each side of the disc or rotor. The rotor has splines
that fit on splines on the hub. The hub fastens to the
motor armature shaft with a key. The rotor and hub ro-
tate with the armature. There is an adapter plate on one
side of the rotor and an armature plate on the other side.
Springs push the armature plate against the rotor to
force the rotor against the adapter plate. An electro-
magnet pulls the armature plate away from the rotor.
An adjustment nut adjusts the spring force.
Each brake has the parts shown in FIGURE 2. The dust
cover keeps dirt out of the assembly. The adapter plate
is the mount for the brake assembly. Capscrews fasten
the adapter plate to the motor housing. Capscrews and
spacers fasten the armature plate and electromagnet as-
sembly to the adapter plate. The housing of the electro-
magnet assembly holds the springs and pins. The ad-
justment nut fastens to the electromagnet housing.
These brakes are for parking and to stop the truck
quickly.
FIGURE 1. BRAKE ASSEMBLY
1. BRAKE ASSEMBLY
2. ELECTROMAGNET HOUSING
3. ADJUSTMENT NUT
4. DUST COVER
5. ARMATURE PLATE
6. ROTOR
7. ADAPTER PLATE
8. MOTOR HOUSING
9636
11645
1
2
3
4
5
6
7
8
1
2
FIGURE 2. BRAKE PARTS
1. DUST COVER
2. ADAPTER PLATE
3. ROTOR
4. ARMATURE PLATE
5. SPRING
6. PIN
7. HUB
8. SPACER
9. ADJUSTER NUT, R40EH ONLY
10. ELECTROMAGNET
11. CAPSCREW
12. CENTER ADJUSTMENT NUT
13. SNAP RING, R40EH ONLY
10791
REPAIRS
CAUTION
The brakes cannot be released mechanically. If the
truck must be moved and there is