GM Service Manual Online
For 1990-2009 cars only

Removal Procedure


Object Number: 404475  Size: SH

The floor pan assembly comes complete including the lower rails, crossbar, rear floor extension and various other components.

Important: One side inner and outer wheelhouses must be removed when replacing the entire sub-assembly.

  1. Remove all related panel and components.
  2. Visually inspect and restore as much of the damage as possible.
  3. Remove the following as necessary:
  4. • Sealers
    • Sound deadeners
    • Anti-corrosion materials

    Object Number: 404476  Size: SH
  5. Remove 4 inner reinforcements (2-dynamic side impact braces-front; 2-floor pan braces-rear) to access the spot welds.

Installation Procedure


    Object Number: 404475  Size: SH
  1. Prepare the mating surfaces with a suitable weld-through primer.
  2. Important: In any area damaged beyond recognition, space plug weld holes every 40 mm (1 1/2 in) apart.

  3. Drill 8 mm (5/16 in) plug weld holes along all mating surfaces except where the floor mates to each wheelhouse.
  4. Position the service floorpan and check for proper fit. Use three-dimensional measuring equipment.
  5. Clean and prepare all welded surfaces.
  6. Important: Prior to refinishing, refer to GM 4901M--2000 "GM Approved Refinish Materials for recommended products. Do not combine paint systems. Refer to paint manufacturer's recommendations.

  7. Apply an approved anti-corrosion primer to all bare metal surfaces.
  8. Apply body sealers and finish as necessary.
  9. Install all related components previously removed for access.