PREVENTIVE MAINTENANCE AIR SYSTEM
Regional Haul
(R05/10) Y53-6033 – 193 –
• Maintain the air compressor to prevent excessive oil
by-pass. See the Maintenance Manual for mainte-
nance details.
• Replace worn seals in valves and air motors as they
are needed. Your Peterbilt Dealer carries rebuild kits
for most units.
Dual Air Gauge and Air Leaks
Your Regional Haul vehicle comes with a primary and
secondary air pressure guage. The gauge indicates the
amount of air pressure in pounds per square inch (psi).
See “
Primary (Secondary) Air Pressure Gauge (Air Res-
ervoir)” on page 42.
If the pressure in either or both systems is too low for nor-
mal brake operation, i.e., either pointer falls below 60 psi
(414 kPa), a warning light on the gauge will glow and the
audible alarm will sound. If the light and alarm do not turn
off at start-up, do not try to drive the vehicle until the prob-
lem is found and fixed.
WARNING! Do not operate the vehicle if leak-
age in the air system is detected. Conduct the
following procedure and contact an Autho-
rized Service Center (or any other properly
equipped service center) if a leak is detected.
Failure to check the brakes or follow these
procedures could cause a system failure,
increasing the risk of an accident resulting in
death or personal injury.
Follow the procedure below to check the compressed air
system for leaks:
1. Periodically, or after maintenance or replacement of
air system components:
2. Build up air pressure in the system to the governor
cut-out point or until 120 psi (827 kPa) is reached.
3. Stop the engine and release the service brakes.
4. Without applying the brake pedal, observe the rate of
air pressure drop. This rate should not exceed 2.0 psi
(14 kPa) per minute.
5. Start the engine and build up the air pressure again.
6. Stop the engine, and apply the brakes fully. Apply the
brake pedal and hold it down for five minutes. The
pressure drop should not exceed 3.0 psi (21 kPa) per
minute.
