Z Height Measurement

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.

IMPORTANT: All dimensions are measured vertical to the ground. Cross vehicle Z heights should be within 12 mm (0.47 in) to be considered correct.
1. Jounce the front and rear suspension to obtain at least 38 mm (1.5 in) deflection, then allow the vehicle to settle.
Fig 1: Z Height Measurement
Courtesy of GENERAL MOTORS CORP.
2. Set the top edge of the level on the reference surface of the steering knuckle (c) and extend the level directly under the rear end of the front attachment bolt of the lower control arm (a).
3. While keeping the level in contact with the knuckle reference surface, adjust the level up/down until the bubble indicates it is horizontally level.
4. Extend a tape measure straight down from the center of the attachment bolt. The point where the tape measure and the level intersect is your first measurement.
5. Keep the top edge of the level on the reference surface of the steering knuckle (c) and move the level directly under the front end of the rear attachment bolt of the lower control arm (b).
6. Extend a tape measure straight down from the center of the attachment bolt. The point where the tape measure and the level intersect is your second measurement.
7. Average the 2 readings (add them together, then divide by 2) and write down the result.
8. Repeat steps 1 through 7, a total of 3 times, writing down the results.
9. Average the results (add them together, then divide by 3) and this result is your final Z height number.
10. Compare your Z height number with the Service Information Z height specification. Refer to Trim Height Specifications .