Peterbilt Medium Duty Trucks Operator's Manual after 1-07

Using the Brake System
• Pump the brakes - Pumping the brake pedal may
generate enough hydraulic pressure to stop the
vehicle.
• Use the parking brake - The parking or emergency
brake is separate from the hydraulic system. Therefore
it can be used to slow the vehicle.
2. Move a safe distance off the road and stop.
3. Set the parking brake. (See page 36.)
4. Turn on the emergency flasher and use other warning
devices to alert other motorists.
Wet or Overheated Brakes
• Wet Brakes
If you have been driving in heavy rain or deep standing
water, your brakes will get wet. Water in the
brakes can cause them to be weak, to apply
unevenly, or to grab. These conditions can cause a
lack of braking power, wheel lockups, or pulling of the
vehicle to one side or the other.
Avoid driving through deep puddles or flowing water if
possible. If not possible, you should to the following:
• Slow down.
• Place transmission in lower gear.
• Gently press on the brake pedal.
Operating Instructions
• Increase engine speed while keeping light pressure
on the brake pedal for a short distance to dry out the
brake linings.
• Overheated Brakes
While traveling down steep hills, gravity will tend to
speed you up. You must go slow enough that your
brakes can hold you back without getting too hot. If
you ride the brake pedal and the brakes get too hot,
they may “fade”, causing you to press even harder in
an attempt to maintain your desired stopping power.
The brakes may even fade so much that you won’t be
able to slow down or stop at all.
Using lower transmission gears will help keep the
vehicle from going too fast. Using lower gears allows
engine compression and friction to help slow the
vehicle. Be sure to be in the right gear before you
start down a hill, especially if you have a manual
transmission. You could get hung up in NEUTRAL
and lose the benefit of engine braking. “Coasting” is
illegal, and also VERY dangerous.
– 92 – Y53-6008 Medium Duty (R10/06)