GM Service Manual Online
For 1990-2009 cars only

Notice: Some frames are constructed of heat-treated steel. Do not weld or drill these frames. The use of heat in excess of 606°C (1200°F) can weaken, cause distortion, and change the characteristics of the steel.

Frame straightening may be a complicated process and usually requires some special equipment. Only trained technicians should perform a frame straightening procedure.

Conduct a complete analysis of the frame condition before beginning the straightening process in order to determine the correct sequence of steps for the repair procedure. Refer to Minimizing Frame Service Description . Identify the frame material before beginning the repair procedure. Refer to Frame and Underbody Description .

Adhere to the following instructions while conducting the repair procedure:

    • Apply pressure from different directions in order to reverse the flow of damaging forces.
    • Control the temperature and the application of the heat.
    • Heat the frame using a large sized tip (multi-hole heating tip) and a neutral flame. Keep the oxygen opened just enough to remove the feathers or the stringers from the blue center at the tip of the torch.
    • Heat the area that will be stretched as the frame is straightened.
    • Heat the area after exerting sufficient pressure. A slight checking or some silvery cracks will appear on the surface of the metal when heating it at an adequate pressure.
    • Gradually increase the pressure while heating the metal.
    • A red glow is an indication of overheating.