GM Service Manual Online
For 1990-2009 cars only

Use a measuring tram gauge in order to determine the alignment of the underbody. In order to perform the recommended measuring inspections, the tram gauge set must include a vertical pointer capable of reaching 914 mm (36 in).

You may make the following measurements using a tram gauge:

    • Direct point-to-point measurements
    • Measurements you calculate on a horizontal plane (datum line) parallel to the underbody
        For each point to be measured, set one of the following pointers as specified:
       - The height pointer
       - The vertical pointer

Take the point-to-point measurements from the following components:

    • The front structure steering component
    • The suspension component

Ensure that the vertical pointers are equally set.

In some cases, you may directly take point-to-point measurements using one of the following tools:

    • A tape measure
    • An appropriate measuring tool

Measure the dimensions-to-gauge holes to the following areas:

    • The leading edge or center of the holes
    • The flush-to-adjacent surface metal

Refer to Measurements - Underbody Underbody Dimensions for the following information:

    • The alphabetically identified points of measurement
    • The metric-to-English dimensional conversion data