GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2009 🢒 Lucerne 🢒 Body Repair 🢒 Collision Repair 🢒 Rear Compartment Floor Panel Replacement

Removal Procedure

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

    Warning: Sectioning should be performed only in the recommended areas. Failure to do so may compromise the structural integrity of the vehicle and cause personal injury if the vehicle is in a collision.

  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: 1609101 Size: SH

    Note: The rear floor pan service part comes pre-cut at the front edge of the rear body cross member.

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

    6. Object Number: 876976 Size: SH

    Note: Do not damage any adjacent panels or components when cutting or drilling out spot welds.

  6. Locate the rear edge of cross bar #5 from under the vehicle.
  7. Drill several 1/8 in holes in the floor pan only along the rear edge of the rear weld flange of cross bar #5. This will aid in identifying the location from the top side of the floor pan.

    8. Object Number: 1609102 Size: SH
  8. Cut the floor panel following the rear edge of the #5 bar.

    9. Object Number: 1609103 Size: SH
  9. Drill out all the spot welds along rails and the wheelhouses rearward of the cutline and remove the rear compartment floor panel. Note the number and location of welds for installation of the service assembly.

    10. Note: Do not damage any inner panels or reinforcements.

  10. Cut and grind flush the original panel of the rear compartment panel at the rear edge of the #5 crossbar.

Installation Procedure

    Object Number: 1609104 Size: SH
  1. Drill 8 mm (5/16 in) plug weld holes in the service part, as necessary in the corresponding locations noted on the original panel.
  2. Lay out and drill 2 additional rows of 8 mm (5/16 in) plug weld holes on top of the #5 bar weld flanges.
  3. Prepare all mating surfaces for welding, as necessary.
  4. Apply GM-approved Weld-Thru Coating or equivalent to all mating surfaces. Refer to Anti-Corrosion Treatment and Repair.
  5. Position the rear floor pan to the vehicle using 3-dimensional measuring equipment. Clamp the part in place.

    6. Object Number: 1609105 Size: SH
  6. Plug weld accordingly.

    7. Object Number: 1609106 Size: SH
  7. Weld the seam along the front cut edge of the floor panel service part. To create a solid weld along the front of the service part with a minimum of heat distortion , make a stitch weld along the seam with 25 mm (1 in) gaps between each weld.
  8. Clean and prepare all welded surfaces.
  9. Paint the repaired area. Refer to Basecoat/Clearcoat Paint Systems.
  10. Apply the sealers and anti-corrosion materials to the repair area, as necessary. Refer to Anti-Corrosion Treatment and Repair.
  11. Install all related panels and components.
  12. Connect the negative battery cable. Refer to Battery Negative Cable Disconnection and Connection.
  13. Enable the SIR system. Refer to SIR Disabling and Enabling.