MODEL 330 OPERATOR'S MANUAL - Peterbilt Motors Company

Preventive Maintenance
Hydraulic Brake System
Introduction
To operate your vehicle safely, you need some understanding
of its brake systems. Brake adjustment and brake balance
must be set carefully to allow equal stopping forces at all
wheels. Tires are also a very important part of the whole system.
How fast you can stop depends on how much friction
there is between the road and your tires.
All of the following areas are interrelated and must conform
to original specifications:
• wheel size
• tire size
• brake pads
• brake rotors
• front wheel bearings
• front end alignment
• parking brake drum
radius
Once a brake system is set to specifications, changing any
one of its components or any combination of components
may degrade the system. All parts have to work together to
perform as they should.
Brake System
Your brake system is hydraulically operated. Refer to the section
titled “Service Brake Component Inspection” on
page 159 for more information on inspecting the brakes.
Any replacement components in the brake system must meet
the specifications of the original components. Any changes
from the original specifications can affect the performance of
the entire system.
WARNING! Do not use any replacement part in
the brake system unless it conforms exactly to
original specifications. A nonconforming part in
your vehicle’s brake system could cause a malfunction
resulting in an injury accident. Consult
you local dealer for suitable replacement parts.
WARNING! Do not work on the brake system
without the parking brake set, the keys removed
from the vehicle, and wheels chocked securely.
If the vehicle is not properly secured to prevent
inadvertent vehicle movement, it could roll and
cause serious personal injury or damage to the
vehicle.
• Use wood blocks (4 in. X 4 in. X 6 in. or
larger) against the front and rear surfaces of
the tires. Be sure the vehicle cannot move.
Model 330 PB1318 3/01 – 157 –