For 1990-2009 cars

Failure to follow this procedure will compromise the structural integrity of the vehicle.

The front dash panel and the lower plenum are formed from laminated steel. This steel is constructed by bonding 2 pieces of cold rolled steel (1) with a viscoelastic layer of adhesive (2). MIG welding laminated steel does not meet GM Corporate standards for structural integrity. As an alternative, all factory welds will be replaced by using the rivet and adhesive bond method described in the installation portion of this procedure. The rivet and adhesive bond method must only be used in the areas as described in this procedure.

### Removal Procedure

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

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 .

Caution: Refer to Collision Sectioning Caution in the Preface section.

3. Remove all related panels and components.
4. Repair as much of the damage as possible.

Important: Note the number and location of the factory welds for installation of the front side rail rear extension.

5. Remove the sealers and anti-corrosion materials from the repair area, as necessary. Refer to Anti-Corrosion Treatment and Repair .

Important: Drill through the front side rail rear extension only. Do NOT drill into the dash panel or the inner reinforcements.

6. Using an 8 mm (5/16 in) spot-weld remover, locate and drill out the factory welds on the upper weld flange connecting the front side rail rear extension to the dash panel.
7. Using an 8 mm (5/16 in) spot-weld remover, locate and drill out the factory welds on the side weld flange connecting the front side rail rear extension to the outer dash panel.
8. Using an 8 mm (5/16 in) spot-weld remover, locate and drill out the factory welds on the rear weld flange connecting the front side rail rear extension to the dash panel.
9. Remove the damaged front side rail rear extension.

### Installation Procedure

1. Position the front side rail rear extension to the vehicle using 3-dimensional measuring equipment.
2. Clamp the front side rail rear extension in place.
3. Using a 7 mm (17/64 in) bit, drill the rivet attachment holes through the upper weld flange on the front side rail rear extension and the dash panel in the exact locations, as noted from the factory rail.
4. Using a 7 mm (17/64 in) bit, drill the rivet attachment holes through the side and rear weld flanges on the front side rail rear extension and the dash panel in the exact locations, as noted from the factory rail.
5. Remove the front side rail rear extension.

Important: If the location of the original plug-weld holes cannot be determined, or if the structural weld-through adhesive is present, space the plug-weld holes every 40 mm (1.5 in) apart.

6. Drill 8 mm (5/16 in) plug-weld holes in the front side rail rear extension, as necessary, in the remaining locations noted from the original rail.
7. Prepare the plug-weld mating surfaces, as necessary.
8. Apply GM-approved Weld-Thru Coating or equivalent to all mating surfaces. Refer to Anti-Corrosion Treatment and Repair .
9. Prepare the bond mating areas by grinding to bare steel the upper weld flange area of front side rail rear extension and the dash panel mating surfaces. Do NOT damage the corners or thin the metal during the grinding process.
10. Prepare the bond mating areas by grinding to bare steel the side, and rear weld flange areas of the front side rail rear extension and the dash panel mating surfaces. Do NOT damage the corners or thin the metal during the grinding process.
11. Clean the mating surfaces.

Important: The adhesive has a 40-50 mm working time. Do NOT allow the adhesive to cure prior to installing the service rail.

12. Apply a 3-6 mm (1/8-1/4 in) bead of metal panel bonding adhesive GM P/N 12378567 (Canadian P/N 88901675) or equivalent to the upper weld flange area of the front side rail rear extension and the dash panel mating surfaces.
13. Apply a 3-6 mm (1/8-1/4 in) bead of metal panel bonding adhesive GM P/N 12378567 (Canadian P/N 88901675) or equivalent to the side and rear weld flange areas of the front side rail rear extension and the dash panel mating surfaces.
14. Using a small acid brush, spread a coat of adhesive to the upper weld flange area of the front side rail rear extension and the dash panel mating surfaces. Cover all of the bare metal to ensure corrosion protection.
15. Using a small acid brush, spread a coat of adhesive to the side and rear weld flange areas of the front side rail and the dash panel mating surfaces. Cover all of the bare metal to ensure corrosion protection.

Important: Do NOT pull the rail rear extension off of the dash after adhesion. To align the parts, slide the rear extension against the front of the dash.

16. Position the front side rail rear extension to the vehicle using 3-dimensional measuring equipment.
17. Clamp the front side rail extension in place.

Important: Verify proper positioning of the front side rail rear extension prior to riveting and welding.

18. Install the 14 mm (9/16 in) (1) long rivets to the upper and rear weld flange of the front side rail rear extension so that the rivet head contacts the passenger compartment side of the dash panel.
19. Install the 14 mm (9/16 in) (1) long rivets to the side weld flange of the front side rail rear extension and the outer dash panel so that the rivet head contacts the rail side.
20. Remove the excess adhesive from the front side rail rear extension area.
21. Plug weld the remaining holes accordingly.
22. Clean and prepare all of the welded surfaces.
23. Apply the sealers and anti-corrosion materials to the repaired area, as necessary. Refer to Anti-Corrosion Treatment and Repair .
24. Paint the repaired area. Refer to Basecoat/Clearcoat Paint Systems .
25. Install all of the related panels and components.
26. Connect the negative battery cable. Refer to Battery Negative Cable Disconnection and Connection .
27. Enable the SIR system. Refer to SIR Disabling and Enabling .