Before proceeding, refer to General Plastic Repair and Plastic Repair Precautions .

1. Clean and inspect the damaged area. Refer to General Plastic Repair .



2. Clamp or tape the damaged area in order to maintain alignment.
3. Prepare the damaged area for the installation of a backing patch. If the rear of the damage is accessible proceed with steps 4 through 6. If the rear of the damage is not accessible skip to step 7.



4. Scuff the inner surface with a #80 grit disc on a D A sander or by hand if the access is limited.



5. Determine the proper repair material. Refer to Flexible Plastic Part Repair Materials or Rigid Plastic Part Repair Materials .
6. Mix the repair material following the manufacturer's instructions.
7. Apply, follow the manufacturer's instructions, the repair material to the inner surface.



8. Apply a backing patch and skip to step 21. Refer to Backing Patch Fabrication .



9. If the rear of the damaged area is not accessible remove some of the damaged material in order to form an access hole through which you can slip a backing patch.
10. Cut a backing patch from a scrap piece of panel. Refer to Backing Patch Fabrication .
11. Sand the mating surface of the patch.
12. Reach through the access hole and sand the underside of the repair area.



13. Drill 2 holes in the backing patch.
14. Thread a piece of waxed wire through the holes in order to assist in holding the patch in place after installation.
15. Determine the proper repair material. Refer to Flexible Plastic Part Repair Materials or Rigid Plastic Part Repair Materials .
16. Mix, follow the manufacturer's recommendations, the correct repair material.
17. Apply , follow the manufacturer's recommendation, the correct repair material to the mating surface of the patch.



18. Slip the patch through the access hole.
19. Pull up hard on the waxed wire until the repair material squeezes out on all sides.



20. Twist the wire around a piece of wood in order to hold the patch in position until the repair material cures.



21. Cure the repair material according to the manufacturer's instructions.



22. Remove any tape, clamps, or waxed wire used to maintain alignment.



23. On the outer surface of the panel, bevel the damaged area with a #50 grit Roloc disc in order to extend the contact between the repair material and the substrate.



24. Using a D A sander, feather out several inches beyond the damaged area in order to remove any paint or primer from the substrate, and provide a proper adhesion surface.

•	Use a #80 grit disc on rigid panels.

•	Use a #180 grit disc on flexible panels.




25. Carefully and smoothly apply a light coat of repair material to the damaged area.



26. Add mat material as needed to strengthen.
27. Apply a final layer of repair material (1) at a slightly higher level than the surrounding area.



28. Cure the repair material according to the manufacturer's instructions.



29. Rough out the surface using a #80 grit disc on a D A sander or a curved-tooth body file.



30. Finish sanding using a #220-320 grit wet or dry sandpaper on a sanding block.
31. Prime and refinish as necessary. Refer to GM 4901 M-D for a listing of approved materials. Follow the procedures recommended by the material manufacturer.