GM Service Manual Online
For 1990-2009 cars only

Note: The body rear end panel is joined to the quarter panel outer, rear floor side member and rear floor panel. It forms the base for the rear combination lamps and other parts and maintains the rigidity of the rear body. Pay particular attention to twists and parallelism and check mounting of related parts when welding.

This repair procedure gives you the option of using an installation procedure for either metal-inert gas (MIG) welding or adhesive bonding.

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.
  3. Remove all related panels and components.
  4. Repair as much of the damage as possible. Refer to Dimensions - Body.
  5. Remove the sealers and anti-corrosion materials from the repair area, as necessary. Refer to Anti-Corrosion Treatment and Repair.

  6. Object Number: 789111  Size: SH

    Note: Note the number and location of the factory welds for installation of the rear end panel.

  7. Locate and drill out all the necessary factory welds.

  8. Object Number: 789112  Size: SH
  9. Remove the rear end panel.

Installation Procedure (Metal-Inert Gas (MIG) Welding)


    Object Number: 789114  Size: SH

    Note: If the location of the original plug weld holes can not be determined, space the plug weld holes every 40 mm (1½ in) apart.

  1. Drill 8-mm (5/16-in) plug weld holes in the service part as necessary in the locations noted from the original panel.
  2. Prepare all mating surfaces as necessary.
  3. Apply 3M® Weld-Thru coating P/N 05916 or equivalent to all mating surfaces.

  4. Object Number: 789112  Size: SH
  5. Position the rear end panel on the vehicle. Use 3-dimensional measuring equipment to inspect the panel.
  6. Clamp the panel in place.

  7. Object Number: 789116  Size: SH
  8. Plug weld accordingly.
  9. Clean and prepare all of the welded surfaces.
  10. Install all of the related panels and components.
  11. Apply the sealers and anti-corrosion materials to the repair area, as necessary. Refer to Anti-Corrosion Treatment and Repair.
  12. Paint the repaired area. Refer to Basecoat/Clearcoat Paint Systems.
  13. Connect the negative battery cable.
  14. Enable the SIR system. Refer to SIR Disabling and Enabling.

Installation Procedure (Adhesive Bonding)


    Object Number: 884474  Size: SH
  1. Grind the surface of the body mating flanges (1) to bare steel.

  2. Object Number: 874302  Size: SH
  3. Grind the body rear end panel mating flanges (1) to remove the E-coating. Take care not to damage the corners or thin the metal during the grinding operation.
  4. Clean the mating surfaces.
  5. Note: The adhesive has a working time of 40-50 minutes. Do not allow the adhesive to totally cure off the vehicle, as proper alignment of the panel to the body will be difficult.

  6. Apply a bead of metal panel bonding adhesive (2) GM P/N 12378566/7 (Canadian P/N 88901674/5) or equivalent to a thickness of 3-6 mm (1/8 to 1/4 in), to both of the mating surfaces.
  7. Using a small acid brush (3), spread a coat of adhesive to cover all the bare metal surfaces to ensure corrosion protection.
  8. Note: Do NOT pull the panels apart after joined together. Slide the panels against each other to realign the panels.

  9. Install the body rear end panel to the vehicle.
  10. Clamp the body rear end panel into position as required.
  11. Using lacquer thinner remove the excess adhesive from the panel area.
  12. Apply the sealers and anti-corrosion materials to the repair area, as necessary. Refer to Anti-Corrosion Treatment and Repair.
  13. Paint the repair area. Refer to Basecoat/Clearcoat Paint Systems.
  14. Install all related panels and components.
  15. Connect the negative battery cable.
  16. Enable the SIR system. Refer to SIR Disabling and Enabling.