GM Service Manual Online
For 1990-2009 cars only

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 .
  3. Important: Perform full replacement only when a full frame rail assembly is installed. Use overlap procedure for rail sectioning.

    Important: The rear floor pan service part comes pre-cut to the correct length for replacement . The part does not need to be modified.


    Object Number: 811134  Size: SH
  4. Remove all related panels and components.
  5. Remove the sealers and anti-corrosion materials from the repair area, as necessary. Refer to Anti-Corrosion Treatment and Repair .
  6. Visually inspect and repair as much of the damage as possible.
  7. Important: Do not damage any inner reinforcements or panels. Use caution not to damage the welds that attach the frame rail to the wheelhouse if you are not replacing the complete rail assembly.


    Object Number: 811132  Size: SH
  8. Cut the rear compartment panel at the rear edge of the number 5 crossbar.
  9. Locate, mark, and drill out all factory welds. Note the number and location of welds for installation of the service assembly.

  10. Object Number: 811133  Size: SH
  11. Remove the damaged rear compartment panel from the vehicle.

Installation Procedure

    Important: This part has structural weld-thru adhesive in the joint areas. Replace this part with additional spot welds at the attachment points. This can be accomplished by adding an additional weld between each factory weld.


    Object Number: 811134  Size: SH
  1. Prepare the mating surfaces as necessary.
  2. Drill 8 mm (5/16 in) plug weld holes along the front edge of the service part. Locate these holes 13 mm (½ in) from the edge of the service part spaced 40 mm (1½ in) apart.
  3. Drill 8 mm (5/16 in ) plug weld holes in the service part, as necessary, in the locations noted from the original panel . Do not drill holes in the vertical flange along the wheelhouse area . This area will be bonded.
  4. Apply 3M Weld-Thru Coating P/N 05913 or equivalent to all mating surfaces.
  5. Apply bonding material Lord 108 to the vertical flanges in the wheelhouse areas only.
  6. Install and align the service part using 3-dimensional measuring equipment.

  7. Object Number: 811131  Size: SH
  8. Plug weld accordingly.

  9. Object Number: 811135  Size: SH
  10. To create a solid weld along the front of the service part with a minimum of heat distortion , make a 25 mm (1 in) stitch weld along the seam with 25 mm (1 in) gaps between them. Then go back and complete the weld.
  11. Clean and prepare all welded surfaces.
  12. Paint the repaired area. Refer to Basecoat/Clearcoat Paint Systems .
  13. Apply the sealers and anti-corrosion materials to the repair area, as necessary. Refer to Anti-Corrosion Treatment and Repair .
  14. Install all related panels and components.
  15. Connect the battery ground (negative) cable. Refer to Battery Negative Cable Disconnection and Connection .
  16. Enable the SIR system. Refer to SIR Disabling and Enabling .