Peterbilt 579 - Suspension Systems

SUSPENSION
4
SUSPENSION
Setting Ride Height
Vehicles equipped with rear air
suspensions have their ride height and
axle (pinion) angle(s) preset at the
factory. These are precision settings
and should not be altered. Incorrectly
adjusted ride height may result in
improper interaxle U-joint working
angles. This can result in pre-mature
driveline wear and driveline vibration.
If your vehicle is equipped with a
Peterbilt rear air suspension, and if it
becomes necessary to reset the ride
height, you may temporarily set it by
following the next procedure. Proper
ride height measurement and values
for a fully laden vehicle are shown in
the illustration and table below.
Ride Height Measurement (Location
for Tandem Axles Shown)
Fully Laden Vehicle
Proprietary
Rear
Ride Height,
inches (mm)
Air
Suspension
Single Drive
Tandem
Drive
Air Leaf
N/A 11.70 (297)
Air Trac
11.00
(279) 11.00 (279)
Low Air
Leaf 6.50 (165) 8.50 (216)
Low Low
Air
Leaf
N/A 6.50 (165)
FLEX Air
N/A 8.50 (216)
Follow this procedure to temporarily
set ride height.
Ensure that
a vehicle is parked and the
wheels chocked before beginning this
procedure.
WARNING!
Unladen Vehicle
Proprietary
Rear
Ride Height,
inches (mm)
Air
Suspension
Single Drive
Tandem
Drive
Air Leaf
N/A 12.0 (305)
Air Trac
11.38
(289) 11.38 (289)
Low Air
Leaf
(Before April
2004)
8.75 (222) 8.75 (222)
Low Air
Leaf
(After April
2004)
6.75 (171) 8.75 (222)
Low Low
Air
Leaf
N/A 6.75 (171)
FLEX Air
N/A 8.75 (222)
4-48 Y53-6047–2C (04/13)