Trim Height Measurements
Trim height is a predetermined measurement relating to vehicle ride
height. Incorrect trim heights can cause bottoming out over bumps, damage
to the suspension components and symptoms similar to wheel alignment
problems. Check the trim heights when diagnosing suspension concerns
and before checking the wheel alignment.
Perform the following before measuring the trim heights:
- Set the tire pressures to the pressure shown on the certification
label. Refer to
Vehicle Certification Label
in General Information.
- Check the fuel level. Add additional weight if necessary to simulate
a full tank.
- Make sure the rear compartment is empty except for the spare tire.
- Make sure the vehicle is on a level surface, such as an alignment
rack.
Z Height Measurement
- Lift the front bumper of the vehicle up about 38 mm (1.5 in).
- Remove your hands.
- Allow the vehicle to settle into position.
- Repeat this jouncing operation 2 more times for a total of 3 times.
- Measure from the pivot
bolt center line (3) down to the lower corner (5) of the lower ball joint
(1) in order to obtain the Z height measurement (4).
- Push the front bumper of the vehicle down about 38 mm (1.5 in).
- Remove your hands.
- Allow the vehicle to rise.
- Repeat the operation for a total of 3 times.
- Measure the Z dimension.
- The true Z height dimension number is the average of the high
and the low measurements. Refer to
Trim Height Specifications
.
Z Height Adjustment
- For vehicles equipped
with a torsion bar suspension turn the bolt (1) that contacts the torsion
arm clockwise to raise the and counterclockwise to lower the height adjustment.
One revolution of the bolt (1) into the nut increases the Z height by
approximately 6.0 mm (0.2 in).
- For vehicles without torsion bars, replace damaged or worn components
as necessary.
D Height Measurement
The D height dimension measurement determines the proper rear end ride
height. There is no adjustment procedure. Repair may require replacement
of suspension components.
- With the vehicle on a flat surface, lift upward on the rear bumper
38 mm (1.5 in).
- Remove your hands.
- Allow the vehicle to settle into position.
- Repeat the jouncing operation 2 more times for a total of 3 times.
- The D height
is obtained by measuring the distance between the edge of the jounce cup
along the jounce bumper center line and the jounce pad on the rear axle.
- The true D height dimension number is the average of the high
and the low measurements. Refer to
Trim Height Specifications
.
- If these measurements are out of specifications, inspect for the
following conditions:
• | Sagging front suspension |
• | Sagging rear coil springs |
• | Proper air suspension operation. |
• | Worn rear suspension components. |
• | Improper tire inflation |
• | Improper weight distribution |