GM Service Manual Online
For 1990-2009 cars only

Front Inner Hinge Pillar Body Replacement Laminated Steel Dash


Object Number: 1640829  Size: SH

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

The front of the dash panel and plenum lower are formed from laminated steel. This steel is constructed by bonding 2 pieces of cold rolled steel (1) with a viscosities layer of adhesive (2). MIG welding laminated steel does not meet GM Corporate standards for structural integrity. As an alternative, all factory welds may 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 described in this procedure.

Removal Procedure

    Warning: Refer to Approved Equipment for Collision Repair Warning 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.

  3. Object Number: 1640832  Size: SH
  4. Remove the sealers and anti-corrosion materials from the repair area, as necessary. Refer to Anti-Corrosion Treatment and Repair.
  5. Visually inspect the damaged area. Repair as much of the damage as possible. Refer to Dimensions - Body.

  6. Object Number: 1640843  Size: SH
  7. Using an 8 mm (5/16 in) spot weld remover, locate and drill out the factory welds on the weld flange connecting the front inner hinge pillar to the dash panel.
  8. Note: Note the number and location of welds for installation of the front inner hinge pillar.

  9. Locate and drill out all remaining factory welds.

  10. Object Number: 1640838  Size: SH
  11. Remove the front inner hinge pillar from the vehicle.

Installation Procedure


    Object Number: 1640841  Size: SH
  1. Position the service front inner hinge pillar in the vehicle using 3-dimensional measuring equipment. Clamp the front inner hinge pillar in place.

  2. Object Number: 1640845  Size: SH
  3. Using a 7 mm (17/64 in) bit, drill the rivet attachment holes into the service hinge pillar through the dash and the lower rail extension in the locations as noted from the factory front inner hinge pillar.

  4. Object Number: 1640847  Size: SH
  5. Remove the service front inner hinge pillar.
  6. Note: If the location of the original plug weld holes can not be determined, space the plug weld holes every 40 mm (1 1/2 in) apart.

  7. Drill 8 mm (5/16 in) plug weld holes as necessary in the locations noted from the original assembly.
  8. Prepare the MIG weld mating surfaces as necessary.
  9. Apply GM-approved Weld-Thru Coating or equivalent to all mating surfaces. Refer to Anti-Corrosion Treatment and Repair.

  10. Object Number: 1640856  Size: SH

    Note: Do not damage the corners or thin the metal during the grinding process.

  11. Prepare the bonding mating areas by grinding to bare steel the surface of the dash panel and the service front inner hinge pillar flanges.

  12. Object Number: 1640857  Size: SH
  13. Apply a 3-6 mm (1/8-1/4 in) bead of metal panel bonding adhesive P/N 12378567 (Canadian P/N 88901675) or equivalent to the mating surfaces of the dash panel and the front inner hinge pillar service panel.

  14. Object Number: 1640858  Size: SH
  15. Using a small acid brush, spread a coating of adhesive on the mating surfaces. Cover all of the bare metal to ensure corrosion protection.
  16. Note: Do not pull the front inner hinge pillar off of the dash after adhesion. To align the parts, slide the front inner hinge pillar against the dash panel.

  17. Position the service front inner hinge pillar to the vehicle using 3-dimensional measuring equipment. Clamp the front inner hinge pillar in place.

  18. Object Number: 1640859  Size: SH

    Note: Verify the proper positioning of the service front inner hinge pillar prior to riveting and welding.

  19. Install the 14 mm (17/32 in) long rivets to the front of the dash flange panel.

  20. Object Number: 1640860  Size: SH
  21. Remove the excess adhesive from the front inner hinge pillar bond rivet area.

  22. Object Number: 1640861  Size: SH
  23. Plug weld accordingly.
  24. Clean and prepare all of the welded surfaces.
  25. Apply the sealers and anti-corrosion materials to the repair area, as necessary. Refer to Anti-Corrosion Treatment and Repair.
  26. Paint the repaired area. Refer to Basecoat/Clearcoat Paint Systems.
  27. Install all related panels and components.
  28. Connect the negative battery cable. Refer to Battery Negative Cable Disconnection and Connection.
  29. Enable the SIR system. Refer to SIR Disabling and Enabling.