GM Service Manual Online
For 1990-2009 cars only

Notice: Do not heat the frame beyond 606° C (1200° F). Overheating will cause distortion and stretching, as well as a change in the characteristics of the metal.

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 Frame Conditions and Minimizing Frame Service Description . It is also important to 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.