Medium Duty Operator's Manual - Peterbilt Motors Company
Medium Duty Operator's Manual - Peterbilt Motors Company
Medium Duty Operator's Manual - Peterbilt Motors Company
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USING THE BRAKE SYSTEM<br />
Use engine compression to assist the service brakes by<br />
not depressing the clutch pedal until the engine reaches<br />
idle speed.<br />
Overheated Brakes<br />
Under normal braking conditions, the energy generated<br />
will bring the internal brake drum temperature to about<br />
500°F (260°C). This is well within the safe zone: the maximum<br />
safe temperature of lining for drum type brakes is<br />
usually about 800°F (427°C).<br />
But if service brakes are used for emergency braking,<br />
used improperly, or for prolonged periods, internal brake<br />
drum temperatures may exceed 800°F (427°C). Such<br />
brake overheating may be detected by a burning smell or<br />
smoke coming from a drum. If this occurs, you should<br />
immediately stop and check for cracked brake drums or<br />
lining fires. If neither exists, get back behind the wheel and<br />
resume a slow speed as soon as possible to cool the<br />
brakes. If the vehicle was to remain stopped, the heat<br />
transfer could destroy the linings and distort the brake<br />
drum.<br />
STARTING AND OPERATING THE VEHICLE<br />
To prevent drums from distortion while they cool down:<br />
• Park the vehicle on level surface and block the<br />
wheels.<br />
• Release the parking brake and allow the brakes to<br />
cool down. See page 103.<br />
Anti-Lock Braking System<br />
This vehicle may be equipped with an anti-lock braking<br />
system (ABS). This ABS reduces the possibility of wheel<br />
lock-up. If a wheel is about to lock during braking, the ABS<br />
will automatically adjust air pressure to the brake chambers<br />
on the appropriate wheel(s) to prevent wheel lock-up.<br />
The ABS is automatically turned on when the ignition<br />
switch is turned on.<br />
ABS Warning Lamps<br />
Truck/Tractor ABS Warning Lamp<br />
A truck/tractor ABS warning lamp illuminates when the<br />
ignition switch is first turned on and will remain on until the<br />
system self-test has been completed successfully. Normally,<br />
the ABS lamp will remain on until a speed of no<br />
more than 9 mph has been reached and the speed sensors<br />
have been checked for correct output. The lamp<br />
– 110 – Y53-6008A <strong>Medium</strong> <strong>Duty</strong> (R05/09)
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