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

Preventive Maintenance
Constant manual adjustment of automatic slack adjusters
can shorten the life of the internal clutch. If the installation
appears to be free of damage, but the applied stroke range
could not be achieved, the slack adjuster must be replaced.
NOTE: The brake adjuster alone does not ensure
proper brake operation. Inspect all brake components.
All brake components work together and
must be checked periodically to ensure the brake
system works properly. See the “Medium Duty
Maintenance Manual” for more information on
brake 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.
Brake System
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.
Your brake system is hydraulically operated. Refer to the section
titled “Service Brake Component Inspection” on
page 155 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.
Medium Duty (R10/06) Y53-6008 – 153 –