Article No. 02-18-6 (SUSPENSION - CNG EXTENDED RANGE
VEHICLES SITTING LOW IN REAR)
Publication Date: September 10, 2002
FORD: 1998-2002 CROWN VICTORIA
Some CNG Extended Range vehicles may appear to sit low in the rear. This
may be caused by the rear springs.
Replace the existing springs with revised springs. The revised springs
provide a higher ride height at curb weight and reduce the possibility of
the rear being too low. Refer to the following Service Procedure for details.
Verify that the vehicle is low in the rear by measuring the ride
height "D" dimension, at curb height. At curb conditions the vehicle should
have full fluids but no additional weight of passengers or instrumentation.
To properly measure ride height, pull the vehicle onto an alignment
rack, place the transmission in park, and do not set the parking brake. Pull
the pins constraining the wheel pads then bounce the vehicle four times with
amplitude of two inches per bounce to neutralize the suspension. If you
do not have an alignment rack with floating wheel pads, you must roll the
vehicle (forward or backward) four feet before you bounce the vehicle. Measure
the ride heights as defined in the following steps.
For rear ride heights:
Measure from the top of the axle tube to the underside of the frame
The rear ride height measurement should be 5.2 inches (+/- .3)
or 137 mm to 153mm.
If below specification, Replace rear springs with updated part
Follow the spring removal and installation procedure found in
the Workshop Manual Section 204-02-29.
After completion, remeasure the ride height to verify repair.
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