Trim Height Inspection

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:
1. Set the tire pressures to the pressure shown on the certification label. Refer to Label - Vehicle Certification (who RPO Z49) or Label - Vehicle Certification (w/ RPO Z49).
2. Check the fuel level. Add additional weight if necessary to simulate a full tank.
3. Make sure the rear compartment is empty except for the spare tire.
4. Make sure the vehicle is on a level surface, such as an alignment rack.
5. Close the doors.
6. Close the hood.
7. All dimensions are measured vertical to the ground. Trim heights should be within 13 mm (0.5 inch) to be considered correct.


Z Height Measurement

Important: K models only the Z height must be adjusted before the alignment.

The Z height dimension measurement determines the proper ride height for the front end of the vehicle. Vehicles equipped with torsion bars use a adjusting arm in order to adjust the Z height dimension. Vehicles without torsion bars have no adjustment and could require replacement of suspension components.
1. Lift the front bumper of the vehicle up about 38 mm (1.5 inch).
2. Gently remove your hands.
3. Allow the vehicle to settle into position.





4. Repeat this jouncing operation 2 more times for a total of 3 times.
5. 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).
6. Push the front bumper of the vehicle down about 38 mm (1.5 inch).
7. Gently remove your hands.
8. Allow the vehicle to rise.
9. Repeat the operation for a total of 3 times.
10. Measure the Z dimension.
11. The true Z height dimension number is the average of the high and the low measurements. Refer to Trim Height Specifications.


Z Height Adjustment





1. 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 inch).
2. 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.
1. With the vehicle on a flat surface, lift upward on the rear bumper 38 mm (1.5 inch).
2. Gently remove your hands. Allow the vehicle to settle into position.





3. Repeat the jouncing operation 2 more times for a total of 3 times.
4. Measure the D height by measuring the distance between the bumper bracket and the top of the rear axle tube.
5. Push the rear bumper downward to 38 mm (1.5 inch).
6. Gently remove your hands. Allow the vehicle to settle into position.
7. Repeat the jouncing operation 2 more times for a total of 3 times.
8. Measure the D height dimension.
9. The true D height dimension number is the average of the high and the low measurements. Refer to Trim Height Specifications.
10. If these measurements are out of specifications, inspect for the following conditions:
- Sagging front suspension Refer to Front Coil Springs Replacement or Torsion Bar Replacement.
- Sagging rear leaf/coil springs Refer to Leaf Spring Replacement or Coil Spring Replacement.
- Worn rear suspension components, such as leaf spring bushings Refer to Spring Bushing Replacement.
- Improper tire inflation Refer to Tire Inflation Pressure Specifications.
- Improper weight distribution
- Collision damage