Operation and maintenance manual

Section 170-0010
1
SM 2253 10-03
SM - 2648
WARNINGS
Use only hydraulic oils meeting specifications
outlined in Section 300-0020, LUBRICATION
SYSTEM. Do Not use Brake Fluid (J1703). Use
of improper fluids is destructive to rubber
components of brakes resulting in loss of
braking and possible catastrophic failure.
Exercise extreme caution while working
on the braking system. Braking system actuating
pressure is 138 ± 6.9 bar (2 000 ± 100 lbf/in²).
DESCRIPTION AND OPERATION
Numbers in parentheses refer to Fig. 1, unless
otherwise specified.
The parking brake consists of a sliding calliper acting
on a brake disc on a rear drive line. The parking brake
is of 'Inverted Design' i.e. requiring pressure to hold the
parking brake off.
Operation is by a spring applied/hydraulically released
actuator (9). Actuator (9) is connected through slack
adjuster (3) to the power screw shaft (19, Fig. 2) that is
screwed into piston (6, Fig. 2) in calliper head
assembly (2). Calliper head assembly (2) slides on
anchor plate guides in bracket assembly (1) bolted to
the frame. Slack adjuster (3) automatically maintains
brake clearance after each application through the
control strap (12). Control strap (12) connects the slack
adjuster (3) to the cap assembly (13).
A push control on the dash panel activates the solenoid
on the brake manifold valve, controlling oil pressure
from the rear brake circuit accumulator to actuator (9).
Application of the push control releases oil from
actuator (9) allowing internal springs in the actuator to
apply the parking brake. Pulling out the push control
directs oil pressure from the rear brake circuit
accumulator to actuator (9), compressing internal
springs, to release the parking brake.
Note: The parking brake is automatically applied when
Fig. 1 - Parking Brake Mounting
1 - Bracket Assembly
2 - Calliper Head Assembly
3 - Slack Adjuster
4 - Bolt
5 - Washer
6 - Nut
7 - Clevis Pin
8 - Cotter Pin
9 - Actuator
10 - Nut
11 - Washer
12 - Control strap
13 - Cap assembly
14 - Slack adjuster screw
15 - Bolt
9
1110
7,86
2
12
15
1
3
4
14
13
5
PARKING BRAKE - Parking Brake and Mounting