PART 8: MAINTENANCE AND SERVICE BRAKE ADJUSTMENT
(R05/10) Y53-6032 – 175 –
• Watch the rate of air pressure drop registered by the
air gauge. The rate of drop should not be more than 3
psi (21 kPa) per minute.
• If you find excessive leakage, a leakage test should
be made at the air line connections and at all air brake
control units. To perform a leakage test, refer to the
detailed instructions in the Peterbilt Maintenance
Manual, or take your vehicle to an authorized Peterbilt
dealer.
Air Disc Brakes
Have brake pads inspected by a qualified mechanic for
wear at regular intervals according to the “Preventive
Maintenance Schedule” on page 143. In severe service or
off-highway applications inspect the linings more fre-
quently.
Regularly inspect for pad/rotor wear:
• Park on level ground and chock the wheels.
• Temporarily release the parking brakes.
• Compare the relative position of two notches; one
located on the caliper and the other on the carrier.
See the illustration below to determine if the brakes
require a detailed inspection by a qualified mechanic.
• Have a qualified mechanic perform a detailed inspec-
tion if the notches are not found. The pads and rotors
should be measured and compared against the man-
ufacturers specifications located in the brake manu-
facturer’s service manual.
Regularly inspect caliper for Running Clearance:
• Stop the vehicle on level ground and let the brakes
cool down. Hot brake calipers can burn skin on con-
tact.
• Chock the wheels.
• Temporarily release the parking brakes.
• Grab the caliper and move it. This movement is Run-
ning Clearance.
Y53-6032.book Page 175 Monday, May 24, 2010 3:37 PM