Loosen the jam nut (A) and un-thread the
adjustment rod (B) from the chamber to
reduce tension on the cable (C). Continue
to un-thread the adjustment rod all the
way and remove it from the chamber.
Air Brakes
WARNING
This control is used for parking only.
Do not leave the vehicle unattended
after setting the parking brake
without placing the transmission park (P).
Use of wheel chocks is also recommended
in hilly or off-road usage.
If the service brakes should fail to operate
while your vehicle is moving, you can make
an emergency stop with the parking brake.
Since the parking brake only applies
stopping power to the rear wheels, your
vehicle’s stopping distance greatly
increases and the handling of your vehicle
is adversely affected. Make repairs
immediately to an inoperative air brake
system circuit.
E210341
Pull the yellow parking brake knob out to
apply the parking brake. Push the knob in
to release the parking brake.
E210346
The parking brake light
illuminates and remains
illuminated (when you switch
the ignition to the on position) until you
release the parking brake.
Releasing Spring Brake with Air
Pressure
The air system in all vehicles with
spring-actuated rear wheel parking brakes
is equipped with a valve located on the
governor for connection to an outside air
supply. The valve lets you recharge the
system with air from an outside source,
releasing the spring-actuated parking
brakes. Your vehicle is now ready to tow in
an emergency.
You can only use an outside air source if
the protected system is in operating
condition. If you cannot restore air pressure
in the protected air system, you must
release the spring-actuated brakes
manually.
Releasing Spring Manually
WARNINGS
Do not attempt to disassemble the
parking brake chamber under any
circumstances. The high spring load
may cause serious injury if the chamber
clamps are removed.
Block the wheels to help prevent the
vehicle from moving.
Unexpected and possibly sudden
vehicle movement may occur if these
precautions are not taken.
If you release air pressure from the spring
brake chamber, the power spring applies
the brake and, unless air pressure can be
re-established, you must release the spring
brake as follows in order to move your
vehicle.
Do not use impact wrenches as they may
damage the piston and prevent proper
caging of the spring. Do not apply more
than 50 lb.ft (68 Nm) to the release bolt
nut.
123
F650750 (TBC), enUSA, First Printing
Brakes