The service part comes with lower quarter panel extension and tail lamp pocket attached. These parts can be left on the vehicle of not damaged. Drill out factory welds on the car and service part and use the outer panel only.

Important: When replacing panels that involve servicing stationary glass, refer to GM Service Bulletin 43-10-48 before performing any priming or refinishing.

Important: Sectioning should be performed only in the recommended areas. Failure to do so may compromise the structural integrity of the vehicle.

Important: It may be necessary to unplug and remove one end of the body wiring harness that runs through quarter pillar lower extension if it is necessary to replace extension.

1. Visually inspect and restore as much of the damage as possible to the factory specifications.
2. Remove all related panels and components.
3. Remove sealers, sound deadeners and anti-corrosion materials as necessary.



4. Determine sectioning locations in rocker area.
5. Mark a line and cut in approved sectioning areas of rocker.
6. In upper quarter panel door opening, locate the fourth weather-strip hole (1).
7. Measure down 25 mm (1 in) and mark a line.
8. On back-glass opening, locate rear edge of roof panel.
9. Measure down 25 mm (1 in) and scribe a second line. Connect marks at both locations to create a cut line.
10. Cut part at marked locations.
11. Locate, mark and drill out all factory welds. Note the number and location of welds for installation of the service assembly.
12. Remove damaged panel. Note placement and number of foam baffles for new installation. If baffles are damaged, replacement service parts are available.

1. Cut service part in corresponding locations to fit original cut lines. Leave a gap of one-and-one-half times the metal thickness of sectioning joint.
2. Create 100 mm (4 in) backing plate on rocker panel from unused portion of service part.
3. Create a 50 mm (2 in) backing plate on sail panel from unused portion of old quarter panel.
4. Drill 8 mm (5/16 in) plug weld holes as noted from original locations. At backing plates, drill 8 mm (5/16 in) plug weld holes 13 mm (1/2 in) from seam spaced 40 mm (1 1/2 in) apart.

1. Position the service part on the vehicle. Check fit using body dimensions.
2. Take service part back off.
3. Prepare mating surfaces.

Important: Prior to refinishing, refer to GM 4901MD-99 Refinish Manual for recommended products. Do not combine paint systems. Refer to paint manufacturer's recommendations.

4. Apply weld through primer to mating surfaces.
5. Install GM P/N 12399117 Sealing Strip between outer wheelhouse and gas door pocket.
6. Weld backing plates into position on body.
7. Position service part and clamp in place. Spot blast plug weld areas. Plug weld as necessary in original locations and along backing plates.
8. Stitch weld along entire sectioning joint. Make 25 mm (1 in) welds along the seam with 25 mm (1 in) gaps between them.
9. Go back and complete the stitch weld. This will create a solid joint with minimal heat distortion.
10. Dress and finish welds as necessary.
11. Install all sealers, sound deadeners and anti-corrosion materials as necessary. Install acoustic foam baffles as noted from original part.
12. Apply two-part catalyzed primer
13. Refinish as necessary.
14. Install all related panels and components.