SECTION 12: BRAKE AND AIR SYSTEM
14
DOB 2490-2789 | X3-45 Commuter PA1605 Maintenance Manual (Final Version – Rev.2 April 2016)
Tool # G34835
to ensure proper pedal angle
(Figure 18).
3. Tighten threaded rod lock nuts to 37-55 lb-ft.
NOTE
When replacing a brake pedal assembly,
make sure to:
Push the brake pedal assembly all the
way toward the front of the vehicle.
Apply blue Loctite (242 or similar medium
strength threadlocker) to the four pedal
retaining bolts.
Torque each of the four retaining bolts to
6-8 lb-ft.
Apply torque seal lacquer to the bolts after
final torque.
15.2 STOPLIGHT
SWITCHES
Two stoplight switches are mounted on the dual
brake application valve (Figure 18). The upper
one is used for the primary air circuit while the
lower one is used for the secondary air circuit.
Both switches have the same purpose, i.e.
sending a signal that indicates when a brake
application is made.
16. PARKING BRAKE ALARM SWITCH
Refer to the appropriate booklet (Bendix, SL-5
Stop Light Switch; reference no. SD-06-2501).
The parking brake alarm uses the same switch
as the stoplights. It is mounted on the spring
brake valve and operates in conjunction with a
NC relay to sound a warning alarm by
completing the electrical circuit when the ignition
switch is turned OFF with parking brake
released.
17. BRAKE RELAY VALVE (R-14)
The primary air system includes three brake
relay valves being supplied by the dual brake
valve, and which function is to speed up the
application and release of the service brakes.
One R-14 valve located in the rear underframe
supplies the drive axle service brake air line,
while the other R-14 valves supplies the tag axle
service brake air line. These valves are
accessible from under the vehicle at the level of
the tag axle.
Maintenance and repair information on these
valves is supplied in the applicable booklet
annexed to this section under reference number
SD-03-1064.
FIGURE 20: R-14
12207
18. ANTILOCK TRACTION RELAY VALVES
(ATR-6)
This valve combines service braking and traction
control as well as electronic stability system
functions. It is located above the front axle.
FIGURE 21: ATR-6
12075
Maintenance and repair information on this valve
is supplied in the applicable booklet annexed to
this section under reference number SD-13-4861
19. SPRING BRAKE VALVE (SR-7)
The spring brake valve is located in the rear
underframe. The SR-7 Modulating Valve is used
in conjunction with a dual air brake system and
spring brake actuator and performs the following
functions:
