Important: The lower rail service part comes as a complete unit, including all brackets and reinforcements. Lower rail replacement instruction sheets are included with the service part. The front extension can also be purchased as a separate service part.

1. Remove all related panels and components.



2. Visually inspect and restore as much to the damage as possible to factory specifications.
3. Cut the rear rail along the rearward flange of the crossbar (1).
4. Continue this cut around the rear rail.
5. Drill out the factory welds on the end of the rear rail inner reinforcement and extension.
6. Move the end of the rear rail inner reinforcement forward, or cut this part and remove it from the rear rail.
7. Cut and bend flange upward (2).
8. Visually inspect and restore as much to the damage as possible to factory specifications.
9. Cut the rear rail along the rearward flange of the crossbar (1).
10. Continue this cut around the rear rail.
11. Drill out the factory welds on the end of the rear rail inner reinforcement and extension.
12. Move the end of the rear rail inner reinforcement forward, or cut this part and remove it from the rear rail.
13. Cut and bend flange upward (2).

1. Use the original part as a guide.
2. Mark a line on the service rail 35 mm (1 5/16 in) forward of the cut made to the original part approximately 535 mm (21 in) without the extension attached to the rail.
3. Cut the service rail along the marked lines and discard the unused section (1).



4. Cut and remove approximately 35 mm (1 5/16 in) along the corners of the service rail to create tabs (1).



5. Step the tabs inward to allow the service rail to fit inside the original rail (1).
6. Position the modified service rail inside the original rail, allow 35 mm (1 5/16 in) of overlap.



7. Check the position of the service rear rail section, use three-dimensional measuring equipment and tack weld in three locations along all three sides of the rail (1).
8. Stitch weld along the entire seam and replace factory welds as necessary.
9. Drill two 8 mm (5/16 in) holes for plug welding each of the three sides of the rail approximately 30 mm (1 3/16 in) from the sectioning joint.
10. Plug weld through the drilled holes into the service rail.
11. Clean and prepare welded surfaces.

Important: Prior to refinishing, refer to GM 4901MD-99 Refinish Manual for recommended products. Do not combine paint systems. Refer to paint manufacturer's recommendations.

12. Apply sealer and anti-corrosion materials as necessary.
13. Prime with two-part catalyzed primer.
14. Install all related components.