BRAKE SAFETY AND EMERGENCY
PART 7: STARTING & OPERATING THE VEHICLE
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Y53-6032
(05/10)
WARNING! Unless you have an anti-lock brak-
ing system, always avoid completely depress-
ing the service brake pedal, if possible, even
during emergency braking. Depressing the
brake pedal too aggressively can cause the
wheels to lock, which can lead to an uncon-
trolled skid and could cause an accident
involving death or personal injury.
Overheated Brakes
Under normal braking conditions, the energy generated
will bring the internal brake drum temperature to about
500° F (260° C). This is well within the safe zone: The
maximum safe temperature of linings for drum type brakes
is usually about 800° F (427° C).
But if service brakes are used improperly or for prolonged
periods, internal brake drum temperatures may commonly
exceed 800° F (427° C). Such brake overheating may be
detected by a burning smell or smoke coming from a
drum. If this occurs, you should immediately stop and
check for cracked brake drums or lining fires. If neither
exists, get back behind the wheel and resume a slow
speed as soon as possible to cool the brakes.
Parking Brakes and Their Use
The yellow diamond-shaped knob on your instrument
panel controls your parking brakes. These are spring
brakes which you activate by releasing air pressure from
their chambers. When they are not in use, air pressure
compresses the springs and releases the brakes. But put-
ting the valve in the Park position exhausts air from the
chambers and allows the springs to extend and apply the
brakes. Also, if your system air drops below the safe oper-
ating level, the spring brakes will apply automatically,
bringing your vehicle to a stop.
WARNING! On trailers built before March 1975
you may not have parking brakes if the trailer
reservoir pressure leaks down. If you depend
on them to hold your vehicle, they could
release, causing a serious accident involving
death or personal injury. These older trailers
have emergency brakes not designed for
parking. They will apply only if there is
enough trailer reservoir pressure. Don’t use
your trailer emergency brakes for parking.
Apply your tractor parking valve too.
Y53-6032.book Page 118 Monday, May 24, 2010 3:37 PM
Summary of Contents for Peterbilt 587
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