Found a spot of rust in my 'rustfree' longhood -- how did it happen?

[techweenie]

This is the most peculiar thing. I've owned this car just short of 7 years; bought it as a basket case and built it up to a pretty decent looking car.

Reason I bought it (and paid "too much" in '03) was that it had no accidents and no rust. So, fast forward 6-1/2 years, and I'm selling it to put money in a new business, and photographing it from every angle, and -- holy moley! I found a rust spot. It's actually rusted through! But it's in the most peculiar place: up at the top of the back brace for the front hood latch.

Can anyone explain how this could happen with an otherwise rustfree car? I'm mystified.

[brads911sc]

Its a 1972 with no galvanized panals. All you need is a scratch to the metal and some humid air and what you see is what you get. Its really not a big deal. You repair it and move on... its not in a critical location.

[techweenie]

Yeah, I'm actually not terribly disturbed by it, but this is a big hole. The car lived in a very dry area and the worst corrosion I'd actually seen was on the floor of the front tub where a palm-sized area had lost its undercoating and had a film of surface rust. So this is just weird. Almost looks like someone used a torch on it and then left it exposed. Trying to do some detective work here with the help of the hive mind.

[brads911sc]

interesting. maybe that cover was replaced at some point? or the front panal where the lock is attached was replaced? very strange indeed...

[Matt Monson]

What if the seals on the badge leaked at some point and water ran down the underside of the hood? Isn't that where it would hit?

[techweenie]

No panels have been replaced anywhere on the car. The car has factory undercoating everywhere, including on this latch brace.

Water coming through the hood crest mounting holes would be deflected by the solid panel over the brace.

This almost seems like it was abraded from the back from something carried in the front trunk (would have been rubbing for a couple decades to do damage like that).

[ossiblue]

I think you may have hit on something with the abrasion from something carried theory. Possibly something sitting on the spare--like the jack--bouncing/rubbing against the metal for ten years could certainly lead to what you have, IMO.

[boxster03]

W. LA does make it strange. No humidity to speak of and very little rain and not a rust prone area. Head scratcher for sure. At least an easy fix.

[Fritter]

If that's all the rust you found on your early car, I wouldn't sweat it....probably a void on the other side where water sat.

[Grady Clay]

Sorry to see that.

Remove the latch assembly.
Look to see if part of the latch has been touching the sheet metal since new.

Best,
Grady

[DanielDudley]

The funny thing about rust is that it acts as it's own sponge for moisture. Once you have a spot, it will hold the water every time it gets wet. You would be better off to grind a solid hole there to metal than to leave it.

[pwd72s]

You might check under the trunk seal...could be a small hole there that allows water to enter while washing the car...

[Mike O'Meara]

I had a similar rust hole just a little lower on the front bulkhead which was caused, I believe, by brake fluid from the vent hose from the brake fluid reservoir. The tube was too short and didn't clear the bulkhead. The undercoat was eaten away and eventually, the metal, too. All this on a basically rust free car.

[Trackrash]

It might be just the picture, but it sure looks like to me like the under coating was burned off by a welding torch.
Something like that makes you worry.
Rocker panels on these old cars will rust through from the INSIDE. (at least that's what happened to mine)
Just driving through puddles is enough to cause the lower front fenders to rust...
Some say you can hear longhoods rusting while parked in the garage.