Peterbilt Medium Duty Trucks Operator's Manual after 1-07

Operating Instructions
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.
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
Driving Tips And Techniques
pumps up to over 100 psi for normal brake operation. If it
does not reach 100 psi, do not try to move the vehicle.
Fifth Wheel
CAUTION: Do not operate a vehicle with air suspension
bags either over- or under-inflated.
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.
Your Medium Duty may be equipped with either a fixed or an
air-controlled sliding fifth wheel. Either type should self-lock
when a trailer king pin trips the locking dogs as the tractor is
backed under a trailer.
Medium Duty (R10/06) Y53-6008 – 105 –