GM Service Manual Online
For 1990-2009 cars only

Removal Procedure

Caution: Refer to Approved Equipment for Collision Repair Caution in the Preface section.

Important: 

   • If the damage exceeds the recommended area for sectioning and the rail cannot be straightened, then replace the entire rail.
   • Sectioning procedures have been developed to simplify the repair of the lower rails, as long as the damage rearward of the sectioning location can be repaired to factory specifications.
   • Failure to follow the instructions may lead to improper rail sectioning, which may compromise the structural integrity of the vehicle.

  1. Disable the SIR system. Refer to SIR Disabling and Enabling .
  2. Disconnect the negative battery cable. Refer to Battery Negative Cable Disconnection and Connection .

  3. Object Number: 1677475  Size: SH
  4. Remove all of the related panels and components.
  5. Repair as much as the damage as possible to factory specifications.
  6. Caution: Refer to Foam Sound Deadeners Caution in the Preface section.

  7. Note the location and remove the sealers and anti-corrosion materials from the repair area, as necessary. Refer to Anti-Corrosion Treatment and Repair .
  8. Perform the necessary procedures to gain access to the repair.

  9. Object Number: 1677477  Size: SH
  10. On the outboard side of the rail, locate the upper reinforcement bracket (1). On the bottom of the rail, locate the lower reinforcement bracket (2).
  11. Measure 280 mm (11 in) (a) forward from the edge of the upper reinforcement bracket (1). Make a mark.
  12. Measure 100 mm (4 in) (b) forward from the edge of the lower reinforcement bracket (2). Make a mark.

  13. Object Number: 1677478  Size: SH
  14. Using the two marks, align a sliding square or similar tool (1) square to the surface to the vertical walls of the frame rail.
  15. Scribe a line to both sides of the frame rails.

  16. Object Number: 1677479  Size: SH
  17. Cut the frame rail at the marked location.

  18. Object Number: 1677480  Size: SH
  19. Remove the damaged frame rail section (1) from the vehicle.

Installation Procedure


    Object Number: 1677481  Size: SH
  1. In order to create the rail section service part (1), cut the full rail service part (2).

  2. Object Number: 1677482  Size: SH
  3. On the outboard side of the full rail service part, locate the upper reinforcement bracket (1). On the bottom of the rail, locate the lower reinforcement bracket (2).
  4. Measure 280 mm (11 in) (a) forward from the edge of the upper reinforcement bracket (1). Make a mark.
  5. Measure 100 mm (4 in) (b) forward from the edge of the lower reinforcement bracket (2). Make a mark.

  6. Object Number: 1677485  Size: SH
  7. Using the two marks, align a sliding square or similar tool square to the surface to the vertical walls of the frame rail.
  8. Scribe a line to both sides of the frame rails.

  9. Object Number: 1677488  Size: SH
  10. Cut the frame rail at the marked location.

  11. Object Number: 1677490  Size: SH
  12. Remove the rail section (1) from the full rail service part.

  13. Object Number: 1685384  Size: SH
  14. From the unused portion of the full rail service part, measure, mark, and cut a 50 mm (2-in) (a) section of rail to be used as a sleeve or backing plate for the sectioning joint.
  15. Cut through the top and the bottom of the sleeve to create two individual pieces that can be installed in the near rail section.
  16. Trim the pieces as necessary to provide a flush fit along the inner surface of the new rail section.

  17. Object Number: 1685386  Size: SH
  18. Drill 6 8-mm (5/16-in) (3) plug weld holes in the rail section (1), so that there are 3 holes equally spaced on each side of the rail.
  19. Drill 6 8-mm (5/16-in) (3) plug weld holes in the vehicle rail (2), so that there are 3 holes equally spaced on each side of the rail.
  20. Clean and prepare all of the welded surfaces.
  21. Apply 3M weld-thru coating P/N 05916 or equivalent as necessary.

  22. Object Number: 1685388  Size: SH
  23. Install the 2 sleeve pieces 25 mm (1 in) (a) into the vehicle frame rail.
  24. Plug weld accordingly at each plug weld location.

  25. Object Number: 1685389  Size: SH
  26. Position the service rail section (1) to the existing rail (2).
  27. Maintain a gap (3) of 1 1/2 times the frame rail metal thickness at the sectioning joint. Clamp in place.
  28. Inspect the frame measurements 3-dimensional to ensure proper position of the service rail section.
  29. Plug weld accordingly at each plug weld location.
  30. Inspect the frame measurements 3-dimensional to ensure proper position of the service rail section.

  31. Object Number: 1685391  Size: SH
  32. Stitch weld along the entire sectioning joint. Make 25 mm (1 in) welds along the seam with 25 mm (1 in) gaps between.
  33. Complete the stitch weld (1).
  34. Clean and prepare all of the welded surfaces.
  35. Install all of the related panels and components.
  36. Apply the sealers and anti-corrosion materials to the repair area, as necessary. Refer to Anti-Corrosion Treatment and Repair .
  37. Paint the repaired area. Refer to Basecoat/Clearcoat Paint Systems .
  38. Connect the negative battery cable. Refer to Battery Negative Cable Disconnection and Connection .
  39. Enable the SIR system. Refer to SIR Disabling and Enabling .