rear fender crack 31 SW

[Duffy1]

My 31 sw has a small crack started on the edge of both rear fenders at same location ,about 1;00 oclock rf and 11;00 oclock lf . It was like this when I got the car six months ago and appears to not gotten any worse. I assume this crack will get larger. How do you repair something like this . These are original fenders .
Thanks for your input .

[Bill Stipe]

Oh thats easy just sell the car to me!!
I'm looking for a 31 SW four door all original!

[Duffy1]

Sorry 29 red rocket ,except for body, this 31 town sedan SW is not original (inserted b engine ,4spd od, `35 -16 in wheels ,f100 steering gear ,AC ,tube shocks ,pressurized b w radiator, 12v.etc. etc.).There is a pretty nice original 31 SW on e-bay . $22,500.

[Ed in Maine]

I am no expert with sheet metal but did have to make many repairs on 1932 front fenders for a coupe. I was determined to keep the same fenders that came with the car. So far, the repairs have held. I took some heavier sheet metal and made small backup patches on the underside so that the fender metal would not flex with use. Using a mig welder, I made welds every inch around the patch to the original metal. Then back up on top where the crack is located, I opened the crack slightly so that the weld could get both sides of the crack and the patch underneath. Then you grind the welds back and use body filler to finish the repair. Good luck, Ed

[bart78]

Backing up a weld with another piece of metal is a place for rust to form. I would weld the crack up grind it and finish it up. I have been told by some to drill a hole at the end of the crack to keep it from going ferther.

[Duffy1]

Sponsored Links (Register now to hide all advertisements)

Thanks Ed and Bart for the input .

[jw hash]

First of the wire in the fender is probable broken DO NOT WELD THE WIRE WHERE THE CRACK IS the wire is designed to float in the fender if you have a crack in the fender and the wire is broken you need to open up the fender remove the wire and weld in other wire so that the crack in the fender and the weld on the wire do not line up in the same area or it will crack there again.

[Duffy1]

Thanks JW

[Kevin in NJ]

The right way is to do it on the car. You need them installed so you can insure you have the right curves so the fender bead will be inline and the back edge sitting in the right place.

Play with the fender in place to see how much it can move so you have a better understanding.

First open of the bead carefully and cut back the wire on either side.

With the fender on the body you need to bring the crack together and weld by small fully penetrating spot welds. If you have tig or a very small tip torch then you can hammer the spots each time after they cool to correct for the shrinkage from the heat. If you mig weld you must first grind the weld down smooth then hammer to correct for shrinkage.

Full penetration is critical to a good weld. You must melt the metal on the back side.

A TIG welder make this job MUCH easier. With patience you can do it with other welders.

To grind in to the bead area I like to use a Dremel tool with a fibered cut off wheel.

The last thing is to get the wire welded in place and the bead curved over.

I have metal working hints at my website.

[Duffy1]

thanks Kevin

[28ACoupe]

The only thing I would add to this is drill a small hole at the end of the crack and back up the metal with a piece of copper.

The hole is to stop the crack from going further.

The copper is to allow a full penetration weld while maintaining a relatively smooth backside. The weld will not stick to the copper and it comes out when the weld is finished.

[Duffy1]

thanks 28acoupe

[Superhart]

I have a very similar problem on my 1930 coupe. A small crack appeared on the driver side, front fender in the middle of the “eyebrow“. Just a couple of days ago I took the car to a body shop to look into repairing the crack, and this is what the technician described for me as the recommended repair: First, he planned to drill a small hole through the fender at the end of the crack to stabilize and prevent spread of the crack. I see this was already mentioned in the previous post. he then said that he would take a Dremel with a cut off disc and basically run the cut off disc along the crack, which at this point is only about one and a half inches long. The purpose of this was to clean up the crock and provide a fresh clean metal on either side. Since the crack includes the lip of the fender, he plans to insert A piece of wire into the fender lip and weld around it. He will then weld the entire crack. I can’t remember what gas combination he said that he would use. Then he planned to grind down the weld to match the surface of the fender. He would just repaint the area and blend it in to the fender color. He said that he could do this without even removing the fender from the car. on the underside of the fender weld repair, he would prime and coat with undercoating to prevent recurrent rust. He promised that when finished, no one would be able to tell there had been a repair in that area, unless they completely stripped the paint off the fender. I am no expert, but the way he described it sounded pretty good to me so I am going to go ahead and let him repair the crock. Thank God he won’t even have to remove the fender from the car to do this. The biggest potential issue therefore is to match the red color of my paint.

[BRENT in 10-uh-C]

Originally Posted by Superhart

I have a very similar problem on my 1930 coupe. A small crack appeared on the driver side, front fender in the middle of the “eyebrow“. Just a couple of days ago I took the car to a body shop to look into repairing the crack, and this is what the technician described for me as the recommended repair: First, he planned to drill a small hole through the fender at the end of the crack to stabilize and prevent spread of the crack. I see this was already mentioned in the previous post. he then said that he would take a Dremel with a cut off disc and basically run the cut off disc along the crack, which at this point is only about one and a half inches long. The purpose of this was to clean up the crock and provide a fresh clean metal on either side. Since the crack includes the lip of the fender, he plans to insert A piece of wire into the fender lip and weld around it. He will then weld the entire crack. I can’t remember what gas combination he said that he would use. Then he planned to grind down the weld to match the surface of the fender. He would just repaint the area and blend it in to the fender color. He said that he could do this without even removing the fender from the car. on the underside of the fender weld repair, he would prime and coat with undercoating to prevent recurrent rust. He promised that when finished, no one would be able to tell there had been a repair in that area, unless they completely stripped the paint off the fender. I am no expert, but the way he described it sounded pretty good to me so I am going to go ahead and let him repair the crock. Thank God he won’t even have to remove the fender from the car to do this. The biggest potential issue therefore is to match the red color of my paint.

Wow, this post comes from over a decade ago!!


As to your painter's thoughts. Your car, your money, ...your deal however IMO what he is suggesting is NOT the proper way to make this repair.

To begin with, his advice with suggesting the undercoat would have been the first indicator of a botched repair job. Secondly, him using a cut-off wheel to enlarge the crack is foolish. This crack needs to be fuse-welded with a TIG, -and definitely not use a MIG that will overheat the edges of the crack. Third and most importantly, unless the reinforcing wire in the bead of the fender is repaired by splicing a longer wire by removing an inch or two in either direction of the crack, the fracture will be back in a short amount of driving. Forth and finally, since your painter likely has no idea what brand & type of paint the Red on that fender is, the likelihood of your painter making an undetectable blend to a 'knowledgeable eye 'has the odds of about 1 in a 100 of truly being undetectable. There are more shades of red and black paint than almost any other color.

Considering how easy it is to remove a fender, I would definitely make sure the fender was removed, sanded entirely on the outside and inside, then do a full paint on that fender. Again, your car and your money, but IMHO you are throwing it away having this painter make a repair as you are describing.