Front Inner Fender Mounting Lip Repair

As I disassembled the car I found rust in places I would never have suspected - so it didn't surprise me to find areas of the front inner fender mounting lip eaten away by the tin worm (The image to the right shows the damage on the driver's side). Although I could have gotten by without repairing this area, I decided to go ahead and make the repair while I had the time, equipment, desire and shipwright's disease.

The following step is hard to describe in words. I included a drawing to illustrate the actions necessary to form a recess or "pocket" in the patch panel.
I fashioned the patch panels prior to cutting out the damaged areas. This was necessary because there are recessed "pockets" located in the mounting lip for the fender mounting nuts. To replicate these "pockets" in my patch panels, I used three scrap pieces of sheet metal. I cut one piece the same size as the original recessed "pocket" (I will call this the "pocket piece"). The other two scrap pieces were cut to be about an inch long (this isn't a critical dimension). With the patch panel oriented in the exact manner in which you will be welding it, place the "pocket piece" on the top of the patch panel where you want the recessed pocket to be formed. Place the other pieces on the underside of the patch panel. I used masking tape to hold the pieces in place. When viewing from the side, the horizontal distance between the edges of the scrap pieces should be about 1/16 to 1/8 inch. I hope the image to the left clarifies the idea. When everything is in place, use a vise or a hammer to flatten the strip where the pieces are taped on. This will produce a "pocket" which is the correct depth.

I took this picture while working on the passenger side. This should give you a better idea of how I formed the metal. I have taped pieces of metal on each side of the patch panel. The middle taped piece determines the size of the recessed pocket while the two outside taped pieces are used to form the recess. I used the anvil on my vise and a ball peen hammer to form the recess. I hammered on both sides of the patch panel until I was satisfied with the recess.

This is what the patch panel looked like after I removed the taped pieces of metal. A nice recess which is the same size and depth as the original.

Using the patch panel as a template, I outlined the area to be removed and used an air-powered cutoff tool to make the cuts. I used vise-grips to hold the patch panel in place and tack welded about every 1/4". The image to the left shows the panel being welded in place. The needle-nosed vise-grip held both the new panel and the existing panel together. I tack welded very close to the vise-grip (I almost welded them to the car body on more than one occasion). This kept the patch panel from warping and ruining the alignment. I went back and placed a tack weld between the existing welds. After everything cooled, I completed the weld by stitch welding around the seam and letting the metal cool after every couple of welds. If you look to the right of the welds, you should be able to discern the "pocket" I described in the above steps.

When the weld was complete, I ground the welds smooth and sprayed the finished surface with a zinc-based coating. I haven't drilled out the mounting holes yet. Someone borrowed the tool I need to complete this. Once I have my tool back, I will finish this part of the project and post the pictures.

The passenger side had only one relatively small area that needed repair.

I have cut away the rusted metal. I didn't cut all the way to the vertical portion of the inner fender. I left a slight amount of the mounting lip so I could align the patch panel with vise grips. I have removed paint, scale, and rust by using my grinder with a wire cup. I did this to get rid of rust that was lurking underneath the paint and to make sure I did not severely contaminate the weld.

I am using vise grips to dry fit and ensure alignment of the patch panel.

After I am satisfied with the alignment, I begin to tack weld. Hint - - - Use lots of tack welds and allow the piece to cool after each tack weld is made. This keeps warpage and distortion to a minimum. Do NOT try to weld too much at one time as it will warp the metal and force you to learn other metal working techniques such as metal shrinking. Patience is rewarded when you are welding. Damn - I guess it is possible to get the camera strap in front of the lens. The black streak you see in the photo is the camera strap but you can still see the tack welds.

All of the welding is complete.

The welds have been carefully ground down. Care must be used to prevent overheating the metal or creating thin spots as a result of grinding.

I trimmed the excess metal away and sprayed the repair area with a zinc-based coating. After the paint dried, I used a long straightedge to mark the centerline for the new holes. I laid the straightedge from the center of the existing forward mounting hole to the center of an existing rear mounting hole. Marking along the straightedge gave me my center lines. I used the old fender to determine the exact location for the mounting holes. After reinstalling the fender, I marked the center for the two mounting holes.

I removed the fender and used a 13/32" drill and drilled two holes - one on each side of the center point. Be careful, the metal is relatively thin and the drill bit can tear the metal as it forms the hole. I would practice on a scrap piece of sheet metal to get the feel for how the drill bit will react when it forms the hole.

After I drilled the two holes, I used a hand held "dremel" tool to cut out the remaining metal. I simply eyeballed the cut line and let her rip.

I was pleased with the results. Everything looks like it came from the factory. It will get a coat of 'real' primer before it gets painted.