Medium Duty Operator's Manual - Peterbilt Motors Company

DRIVING TIPS AND TECHNIQUES
Driving with Deflated Air Springs
Vehicles with the air suspension (option): If an air spring
ruptures, there will be enough air pressure to drive the
vehicle to a safe stop off the highway to investigate the
problem.
WARNING! Do not continue to drive with ruptured
air springs. The air loss can cause the
spring brakes to apply allowing your brakes to
drag and burn up the linings, which could lead
to an injury accident. Do not continue to operate
the vehicle in this condition.
To get to a repair facility, do the following:
1. Remove the height control link connected to the axle
and to the suspension air valve control arm. This will
cause the air valve control arm to center in the closed
position.
2. The air system can then be pumped up to normal
pressure for continued operation.
Fifth Wheel
STARTING AND OPERATING THE VEHICLE
WARNING! Low air pressure could make
brakes unsafe for driving by not providing
sufficient air brake application pressure in an
emergency, which could lead to an injury accident.
Before driving the vehicle, make sure
the air pressure pumps up to over 100 psi for
normal brake operation. If it does not reach
100 psi, do not try to move the vehicle.
CAUTION: Do not operate a vehicle with air
suspension bags either over- or underinflated.
This could cause damage to driveline
components. If you must drive under
such conditions, do not exceed 5 mph (8 km/
h).
The following applies to tractor configurations:
WARNING! Ensure that all fifth wheel maintenance,
adjustments, and rebuilding are done
only by a qualified mechanic. An improperly
maintained fifth wheel can cause a trailer to
separate from a tractor. This could lead to an
injury accident and damage to property.
– 134 – Y53-6008A Medium Duty (R05/09)