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 an adjusting arm in order to adjust the Z height dimension. Vehicles without torsion bars have no adjustment and could require replacement of suspension components. Jounce the front and rear suspension to obtain at least 38 mm (1.5 in) deflection, then allow the vehicle to settle.

Fig 1: Locating Point A
Courtesy of GENERAL MOTORS CORP.
IMPORTANT: The left and right Z height difference should be no more than 12 mm (0.47 in).
1. Set the top edge of the level on the reference surface (Point A) of the steering knuckle.
Fig 2: Locating Steering Knuckle Components
Courtesy of GENERAL MOTORS CORP.
2. With the level on the steering knuckle (C), extend the level directly under the rear of the rear 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 or 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, and then divide by 3) and this result is your final Z height number.
8. Repeat steps 1 through 7, a total of 3 times, writing down the results.
9. Average the results (add them together, and 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 .