Procedure to Repair Fiberglass Fenders and Hood{7251, 7252} Caterpillar

Agricultural Tractors:

Challenger 65E (PIN: 6GS)

Challenger 75E (PIN: 6HS)

Challenger 85E (PIN: 6JS)

Challenger 95E (PIN: 6KS)

Introduction

This special instruction provides the necessary procedures that are required to repair defects on the fenders and hoods of the following Challenger Agricultural Tractors:

• Challenger 65E (PIN: 6GS)

• Challenger 75E (PIN: 6HS)

• Challenger 85E (PIN: 6JS)

• Challenger 95E (PIN: 6KS)

This special instruction includes the procedures to repair the following defects:

• Surface defects or scratches on the paint or the gelcoat surfaces

• Gelcoat and minor reinforcement of surfaces

• Structural damage to the fiberglass

• Cracks in the gelcoat

Repair of Surface Defects and Scratches

Paint Repair

1. Sand the surface that has defects and scratches with sandpaper that is 320 grit.

2. Spray the area with the appropriate paint. You should sufficiently overlap the paint. This will allow you to blend the painted area with the surrounding surface.

3. After the paint has cured, rub the surface with a good quality automotive buffing compound. Use the buffing compound to blend the transition area and use the buffing compound to achieve a uniform shine on the surface.

4. Use an automotive wax in order to protect the surface.

Gelcoat Repair

1. Sand the surface defect and scratches with sandpaper that is 180 grit or 220 grit. Feather out the area that is being sanded into the surrounding area. This will allow you to blend the repaired area with the surrounding area.

2. Apply masking tape in order to protect the machine from overspray.

3. Add a catalyst to the gelcoat at approximately 2 percent of the total weight. Spray the repaired area.

4. Sand the repaired area by using wet sandpaper. Use the following sandpaper: 320 grit, 400 grit, 600 grit, 800 grit and 1200 grit. Start with the sandpaper that is 320 grit and then end with the sandpaper that is 1200 grit. Use clean water for each grit of sandpaper in order to eliminate contamination from the previous particles of the sandpaper.

5. Rub the surface by hand with a liquid automotive buffing compound. This will help to achieve the same shine as the surrounding surface.

6. Clean the repaired surface and the entire surface of the machine that is painted with gelcoat.

7. Protect the entire surface of the machine with an automotive wax of good quality. Apply the wax to the surface of the machine that is painted with gelcoat.

Minor Reinforcement of Surface Defects

1. Sand the area that needs to be repaired.

2. Fill the deep scratches with automotive body filler.

3. Allow the automotive body filler to cure.

4. Sand the automotive body filler that has cured with sandpaper that is 180 grit.

5. Clean the surface.

6. Continue the repair procedure by starting Step 1 in ""Gelcoat Repair" ".

Repair of Structural Damage to Fiberglass

Note: The structural damage to the fiberglass can be repaired on one side or on both sides of the fiberglass.

Repair of Structural Damage to Fiberglass (One Side)

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Illustration 1	g00582915
(A) Depth of repair (B) Length of repair

1. Remove the damaged area or grind the damaged area by using either a 24 disc or a 36 disc on a die grinder. The area that is being repaired should be feathered out in order to blend with the surrounding surface. The length of repair (B) should be 12 times depth of the repair (A) .

2. A resin and fiberglass matting will be used to fill in the area that is being repaired. Add a catalyst to the resin at approximately 2 percent of the total weight.

3. Fill in the hollow area with resin and with fiberglass matting. Use pieces of fiberglass matting that are of a small diameter in the deepest area. Feather out the repaired area with pieces of fiberglass matting that are of a larger diameter until you achieve the original thickness of the fiberglass.

4. Allow the repair material to cure.

5. Sand the repair material to a height that is lower than the original surface. This will allow space for the automotive body filler and the gelcoat.

6. Continue the repair procedure by starting Step 1 in ""Minor Reinforcement of Surface Defects" ".

Repair of Structural Damage to Fiberglass (Two Sides)

The repairs of structural damage to the fiberglass (two sides) can be accomplished by using the same procedure that is shown in ""Repair of Structural Damage to Fiberglass (One Side)" ". There are only two differences. The differences are listed below.

Illustration 2	g00583284
(C) Depth of repair (D) Length of repair

• The length of repair (D) should be 6 times depth of repair (C). This is true on both sides of the fiberglass.

• The resin and the fiberglass matting is done on both sides of the fiberglass.

Continue the repair procedure by starting Step 1 in ""Minor Reinforcement of Surface Defects" ".

Repair of Cracks in Gelcoat

1. Grind out the cracks in the gelcoat down to the fiberglass by using a small pencil grinder or by using a Dremel tool.

2. Remove any excess dust and dirt.

3. Fill the areas that have been ground with putty. The putty should be of good quality. The putty should be made of polyester (fiberglass). The putty can be purchased at an automotive parts store.

4. Allow the putty to cure.

5. Sand the repaired area. Use the following sandpaper: 120 grit, 180 grit, 220 grit and 320 grit. Start with the sandpaper that is 120 grit and then end with the sandpaper that is 320 grit.

6. Clean the repaired area.

7. Paint the area that was sanded with an automotive filler/primer. Allow the filler/primer to cure.

8. Sand the primer with sandpaper that is 320 grit.

9. Wipe the area with a tack cloth in order to remove all dust and dirt particles.

10. Spray with the appropriate topcoat paint and allow the repaired area to cure. Continue the repair procedure by starting Step 1 in ""Paint Repair" ".