PART 7: STARTING & OPERATING THE VEHICLE SETTING RIDE HEIGHT
(05/10) Y53-6032 – 139 –
WARNING! The rear of a vehicle will drop
about 3 1/2 inches (88 mm) when the air
springs are deflated. Ensure that no persons
or objects that could be killed, injured or
damaged are under the vehicle before deflat-
ing the air springs.
WARNING! To minimize risk of damage or
death or injury, do not use a dump valve to
deflate the air springs. Rotate the height
control valve(s) manually to ensure positive
control of air spring deflation.
3. Rotate the valve either clockwise or counterclockwise
until air pressure in the air springs provides the ride
height specified for that suspension. Measure the ride
height from the bottom of the frame rail to the approx-
imate centerline of the rearmost drive axle hub:
WARNING! Do not allow the air springs to
overinflate. Overinflating the air springs may
cause them to burst which can lead to death
or personal injury from debris or the frame.
• For tandem axles, make the vertical measurement
at the centerline of the suspension (see illustration
on page 137
).
• For a single axle, make the measurement in front of
the axle, in the area forward of the tires but not past
the suspension bracket.
4. When at the correct ride height, ensure that the height
control valve lever is in the neutral position, then
install either the built-in alignment pin or a 1/8-inch (3
mm) dowel (see page 138
).
5. Torque the mounting fasteners to 55–75 Lb. in. (6.2–
8.5 N.m.).
6. Remove the alignment pin or dowel.
7. Repeat Steps 2 through 6 above for the RH valve on
vehicles with a dual-valve system.
Driving With Deflated Air Springs
If an air spring is ruptured, there will be enough air pres-
sure to drive the vehicle to a safe stop off the highway to
investigate the problem.
Y53-6032.book Page 139 Monday, May 24, 2010 3:37 PM
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