GM Service Manual Online
For 1990-2009 cars only

Object Number: 277403  Size: MH

The front wheelhouse is available as a complete assembly, which includes the inner upper rail and battery tray.

Important: 

   • Perform the following steps when replacing the complete assembly:
      - Remove the extension that is spot welded at the rear of the service assembly in order to modify the left side.
      - Modify slightly the right side.
      - Remove the 2 extensions that are welded at the rear of the service assembly in order to avoid breaking the urethane seal at the dash panel (bulk head).
   • Don't replace the entire wheelhouse assembly when damage is limited to the front portion of the wheelhouse. Use the sectioning procedure.

Removal Procedure


    Object Number: 277406  Size: SH
  1. Remove all related panels and components to gain access to the front wheelhouse.
  2. Visually inspect the damaged area.
  3. Restore as much of the damage as possible to factory specifications.
  4. Remove the sealers and anti-corrosion materials as necessary.

  5. Object Number: 277407  Size: SH
  6. Remove the inner and outer upper rails.
  7. Apply 25 mm (1 in) wide tape along the forward edge of the panel stiffener.

  8. Object Number: 277410  Size: SH
  9. Locate all factory welds.
  10. Important: Note the number and location of welds for installation of the service assembly.

  11. Mark all factory welds.
  12. Drill out all factory welds.
  13. Cut the wheelhouse at the forward edge of the tape to create a 25 mm (1 in) weld flange for installation.
  14. Remove the damaged wheelhouse.

Installation Procedure

Tools Required

3D Measuring Equipment


    Object Number: 277411  Size: SH
  1. Apply 25 mm (1 in) wide tape to the service wheelhouse at the forward of the panel stiffener.
  2. Cut the service wheelhouse rear of the tape
  3. • Create a 25 mm (1 in) overlap for plug welding
    • Leave the inner upper rail attached

    Object Number: 277413  Size: SH
  4. Remove and discard the unused portion of the service wheelhouse.
  5. Important: Locate holes for plug welding 40 mm (1.5 in) apart if the original locations are damaged beyond recognition or a new weld flange is created.

  6. Drill 8 mm (0.31 in) plug weld holes as necessary in the locations noted from the original assembly
  7. Use 3D Tool in order to measure alignment of service wheelhouse in order to ensure proper fit.
  8. Plug weld holes as necessary.
  9. Clean and prepare all welded surfaces.
  10. Important: Do not combine paint systems. Refer to paint manufacturer's recommendations.

  11. Prime with two-part catalyzed primer to all welded surfaces.
  12. Apply sealer and anti-corrosion materials to all welded surfaces as necessary.
  13. Install all related panels and components.