OPERATOR'S MANUAL

Air System Preventive Maintenance
– 198 – Y53-6027
Medium Duty (R05/09)
Periodically: Clean filter screens ahead of the valves by
removing the screens and soaking them in solvent. Blow
them dry with pressurized air before reinstalling them.
CAUTION: Do not use penetrating oil, brake
fluid, or wax-based oils in the air system. These
fluids may cause severe damage to air system
components.
• Maintain the air compressor to prevent excessive oil by-
pass. See the Medium Duty Maintenance Manual for
maintenance 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 Medium Duty vehicle comes with a primary and second-
ary air pressure guage. The gauge indicates the amount of
air pressure in pounds per square inch (psi).
See “Primary
(Secondary) Air Pressure Gauge (Air Reservoir)” on page
43.
If the pressure in either or both systems is too low for normal
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 problem is found
and fixed.
Location of Air Tanks
FRONT
SECONDARY
(SERVICE) TANK
DRAIN VALVE
WET (SUPPLY)
TANK UNDER
REAR PRIMARY
(SERVICE) TANK
02602
FRONT SERVICE
TAN K