How to Repair Plastic Truck Fender

Repairing a plastic truck fender won’t always be a viable option. Because many plastic panels are designed to fold in the event of accidental impact, recovering them at a later stage isn’t always a possibility. However, small splits and dents can be easily rectified without having to purchase replacement parts.

Step 1 - Surface Preparation

Wash the entire surface of your truck fender so that all damage is clearly visible. Take note of any areas that area either dented or split and sand down around the affected areas using P180 grit paper. Be sure to cover an area of 2 inches around the circumference of the repair so that the body filler can be feathered out effectively later in the task.

Step 2 – Splits and Dents

Splits should be pulled together as closely as possible using high adhesive masking tape from behind the fender. You may have to use multiple strips of tape before good adhesion is acquired.

Take the plastic weld solution and distribute a copious amount across over the area where the split has been sealed. Aerosol hardeners which can be sprayed directly on top of the plastic weld solution are usually provided as part of the kit and this dries the repair instantly. If the plastic weld solution sits above the surface of the truck fender, it can be leveled out using P180 paper to leave a small crease.

Next, a layer of polyester-based plastic body filler can be used to fill the remaining creases and dents. Make sure that the body filler sits above the surface of the truck fender and extends beyond the damaged area by a couple of inches.

Step 3 – Preparation

Once the body filler has cured, rub down using P180 grit paper until you have achieved a flat even surface that is consistent with the contours of the truck fender. A dust mask should be worn during this particular stage. Remove the surface dust with a can of compressed air and wet sand the remainder of the fender with P400 grit paper to promote adhesion for the paint and primer. This will also help to remove any furring that has occurred during the repair process.

Step 4 – Priming and Painting

Clean the truck fender carefully so all traces of dust and fibers are removed. The fender can now be masked up to reduce the risk of overspray during the priming and painting process. Apply 2 to 3 coats of aerosol plastic primer and allow to dry. This can be rubbed down with P400 grit paper once it has fully cured.

Clean the fender again and apply the textured fender paint in slight sweeping movements until full coverage is achieved. Make sure the color and texture match your truck fender for a completely seamless repair before unmasking the vehicle.