AIR SYSTEM PREVENTIVE MAINTENANCE
– 194 – Y53-6033
Regional Haul (R05/10)
7. If you detect excessive leakage (air pressure loss
greater than 3.0 psi after five minutes of brake appli-
cation), a leakage test should be made at the air line
connections and at all air brake control units. These
tests should determine where air is escaping.
Air Compressor
Operation
All compressors, regardless of make or model, run contin-
uously while the engine is running. System pressure is
controlled by the governor. The governor acts in conjunc-
tion with the unloading mechanism in the compressor cyl-
inder block to start and stop compression of air. The
compressor is unloaded when the system pressure
reaches 120 psi (827 kPa) and compression is re-estab-
lished when system pressure falls to 100 psi (690 kPa).
Preventive Maintenance
The following service checks are provided for your infor-
mation only and should be performed by a certified
mechanic. Contact your Peterbilt Dealer or consult the
Maintenance Manual and the engine manufacturer's
Maintenance Manual for further information on servicing
air compressors. After completing any repairs to the air
system, always test for air leaks, and check the brakes for
safe operation before putting the vehicle in service.
According to Table 5, “Air System Scheduled Mainte-
nance,” Page 190:
• Inspect compressor air filter element, if so equipped, and
replace element if clogged. Check compressor mounting
and drive for alignment and belt tension. Adjust if neces-
sary.
• Remove compressor discharge valve cap nuts and
check for presence of excessive carbon. If excessive
carbon is found, clean or replace the compressor cyl-
inder head. Also, check compressor discharge line for
carbon, and clean or replace the discharge line if nec-
essary.
• Disassemble compressor and thoroughly clean and
inspect all parts. Repair or replace all worn or dam-
aged parts, or replace compressor with a factory
exchange unit.
