Repairing rear fender rust-through in '48

[doctormap]

I have been pondering what to do to repair the rust-through that has occurred on both rear fenders of my '48 Champion 4-door sedan. It occurs where the sheet metal is doubled up just behind the back doors. The metal is folded over on itself in order to form a flange from top to bottom. The flange is used to bolt the front end of the fender to the car body. Where the metal is doubled up, water (and dirt) is trapped, and this resulted in rust-through, through the outside and inside skin of sheet metal. I have not been able to figure out how to repair this. Should I try to cut out all the rusty metal, and replace both outside and inside skins, or should I leave part of this as one layer of metal only, in order to prevent the same thing from happening again? I wonder if I should just try to weld the flange to the outside skin, and eliminate the inside layer of metal entirely?

doctormap
'48 Champion 4-door

[Roscomacaw]

Doc, the easiest approach would be to find a pair of good 47-48 Champion or Commander rear fenders (for a 4-dr, of course) Barring that, a competent body man would probably have to SEE your car to make an assessment and a strategy for repairs.

Miscreant at large.

1957 Transtar 1/2ton
1960 Larkvertible V8
1958 Provincial wagon
1953 Commander coupe
1957 President 2-dr
1955 President State
1951 Champion Biz cpe
1963 Daytona project FS

[Avalanche325]

One thing I have heard people do in a place that has double metal like this, is to do the repair and then fill the void between the two pieces of metal with either roofing sealer or rust proofing paint. If you fill it completely up, you can't get dirt and water in there.

[rockne10]

Rust-free replacements are your best bet. Rust-free fenders that are no longer as straight as they used to be can yeild good front edges that can be sectioned in by a competent body man or a very patient novice (Boy, is that a learning experience).

Those fenders can be found. There are usually a few at Reedsville and York.

Watch the ads in Turning Wheels or place a free want ad, assuming you're a SDC member.

Your existing fenders can probably be repaired but, Mr. Biggs is right. A competent body man, whom you trust, needs to evaluate their condition and know your desires. Even a competent body man can do a half----d job if that's what he thinks you want to pay for.

I'm not aware of any goop-and I've tried some-that can fill that seam without retaining moisture. Your best bet, once it's done and well primed and painted with something like POR15, is to keep it clean and get under once in a while to squirt in some heavy oil.

[Roscomacaw]

Sad thing is, I know of one or two sets of rear fenders for this car. But while they're for sale, the party that has them won't (as in WILL NOT) hassle with shipping.[V]

Miscreant at large.

1957 Transtar 1/2ton
1960 Larkvertible V8
1958 Provincial wagon
1953 Commander coupe
1957 President 2-dr
1955 President State
1951 Champion Biz cpe
1963 Daytona project FS

[Avalanche325]

The problem with squirting oil around under, and in hidden part of your car is that oil attracts dirt. Dirt attacts moisture. Moisture causes rust. So then after a few years, you have the same old problem on your new body panel.

The back sides and hidden areas should be painted or coated. A double metal area like a fender or rocker flange can be filled in with something like POR-15 to keep dirt from gathering.

I had a 66 Mustang. They are notorious for rusting at the bottom of the doors. This is caused by a little trough where the door bottom and outer skin meet. If you paint the inside of the door and fill that trough with paint (litterally just pour it in), you will never have rust there again. I kept mine as a daily driver for 10 years and the doors were fine when I sold it. It was ungaraged for 7 of those years.

[Roscomacaw]

Avalanche writes: "I had a 66 Mustang. They are notorious for rusting at the bottom of the doors. This is caused by a little trough where the door bottom and outer skin meet. If you paint the inside of the door and fill that trough with paint (litterally just pour it in), you will never have rust there again. I kept mine as a daily driver for 10 years and the doors were fine when I sold it. It was ungaraged for 7 of those years."

Studes have the same problem. Actualy, if folks would get into a routine of taking a pocket knife and running it into the drain slots on the bottoms of Stude doors, they'd probably never see any rust there.
While doing this 58 Provincial's doors and tailgate - I liberally applied POR-15 inside the doors (used a brush in that case) and inside the lower tailgate's lower edge (did the pour and slosh there since it's impossible to get your hand and arm very far inside the assembly.[B)]
Fact is, the pour and slosh method is something I do with ALL the Studes I have apart. Tape up any drain holes or obvious gaps so that the coating won't escape. Then pour in more liquid than you really need and work the part slowly, back and forth.
Once you're satisfied that it's had a chance to permeate all the seams, folds and nooks, pour out the excess or just remove the taped up openings and let it drain out that way.

Of course, you wouldn't wanna do this right after it had rained or during a really damp period of time. No sense trying to TRAP moisture in place. But here where it's hot and dry for half of the year, I feel pretty good about treating doors and lids like this after the piece has spent a day or two in the sun.

Miscreant at large.

1957 Transtar 1/2ton
1960 Larkvertible V8
1958 Provincial wagon
1953 Commander coupe
1957 President 2-dr
1955 President State
1951 Champion Biz cpe
1963 Daytona project FS