operators_manual

Auxiliary Axle Pressure Regulator
Information on using the auxiliary axle
pressure regulator.
Vehicles with liftable auxiliary axles will
have knobs available to adjust the
pressure in the auxiliary axle suspension.
These knobs are in addition to the tag and
pusher axle switches that control the axle
position.
Adding more pressure to the auxiliary axle
will increase the pressure the auxiliary axle
pushes down. Increasing pressure will
decrease load on the drive axles and will
descrease traction. Decreasing pressure
will transfer more weight to the drive axles
and will result in more traction from the
drive axles.
Deflate the auxiliary axle suspension
before coupling or uncoupling a trailer.
After the trailer is coupled or de-coupled,
then increase pressure to balance traction
and axle load requirements. Inflate air
springs of the auxiliary axles to the desired
pressure after coupling to a loaded trailer
while still maintaining proper traction of the
drive axles.
Adjust the pressure regulator control knob
to a lower pressure until desired traction is
obtained. By reducing air pressure at
pusher or tag axle, load will be transferred
to drive axles. Do not overload drive axles.
Always deflate air springs of the auxiliary
axles before attempting to unload vehicle.
This allows maximum traction of the drive
axles to control the vehicle.
Depending on the suspension, various
calibrations may be required. Contact your
authorized dealer or axle/suspension
manufacturer for specific calibration
procedures.
Some suspensions require dump valve
calibration. For example, some dead axles
do not lift, but the air can be dumped out of
them to unload them when empty. Air
pressure is controlled via an adjustable
regulator. These axles need to be
calibrated for load.
Contact your authorized dealer or axle/
suspension manufacturer for dump valve
calibration procedures.
What is Axle Creep Rating
Vehicles outfitted with auxiliary axles, and
full truck configuration, will have an axle
creep rating which defines how much load
is allowed when the vehicle has a full load
and manuevering the vehicle, at very slow
speeds, with auxiliary axles in the up
position. In these situations, the load
exceeds the gross axle wieght rating of the
axles.
Operator's using vehicles equipped with
liftable auxiliary axles must consider creep
ratings when any liftable axle is unloaded
or in the raised position. Liftable auxiliary
axles should only be raised (or unloaded)
to improve maneuverability in an off-road
use or when vehicle is unloaded.
WARNING!
Never operate the vehicle with more pres-
sure in the lift axles than is necessary to
carry the load, as determined by the calibra-
tion procedure described. Failure to do so
can result in loss of traction and stability at
the steer and/or drive axles and can result in
increased braking distance, which could
cause loss of vehicle control resulting in an
accident. Failure to comply may result in
death, personal injury, equipment or proper-
ty damage.
DRIVING - Axle and Suspension
118 Y53-6096-1A1 (01/17)
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