Important: Sectioning procedures have been developed to help simplify the repair of the lower rails, provided the majority of damage can be returned to factory specifications. This allows technicians to repair the damaged front section without having to make a complete rail replacement. Sectioning of the lower rail does not require the removal of the powertrain, although the front cradle must be lowered.

1. Remove all related components and panels.
2. Visually inspect and restore as much of the damage as possible to factory specifications.
3. For the right side repair it may be necessary to remove the alternator and air conditioning compressor.

Important: Inner and outer sectioning templates are available for both the left and right rails. It is important to use the correct template when marking lines for cutting.

4. Align the appropriate inner and outer templates on the damaged lower rail and mark lines as indicated.



5. Cut the rail along the marked lines and remove the damaged portion of the rail (1).
6. Cut and remove approximately 5 mm (1/4 in) of the outboard and downward turned flanges of the lower rail.



7. Cut a 5 mm (1/4 in) gap approximately 5 mm (1/4 in) along the corners of the lower rail to create tabs (1).



8. Step the tabs inward to allow the replacement lower rail section to fit over the original rail (1).
9. Weld all four edges together.

1. Align the inner and outer templates on the service part and mark lines as indicated (1).
2. Cut the service part along the marked lines and discard the unused section.
3. Position the modified service part over the stepped tabs of the original rail, allow 5 mm (1/4 in) of overlap.




Important: When stitch welding, make 25 mm (1 in) welds along the seam (1) with 25 mm (1 in) gaps between.

4. Complete the stitch weld along the seam.
5. Clean and prepare welded surfaces.

Important: Do not combine paint systems. Prior to refinishing, refer to GM 4901MD-99 Refinish Manual for recommended products. Refer to paint manufacturer's recommendations. For further information or to order Manual, call 1-800-269-5100.

6. Apply sealers and anti-corrosion materials as necessary.
7. Prime with two-part catalyzed primer.
8. Install all related panels and components.