Help, my rust free CA car has some rust.

[SoCal911T]

I'm the second owner of this '70t that was delivered to Don Burns Porsche/Audi in Garden Grove, CA. It's never been out of SoCal but it's always lived near the coast.




Some of you might remember, this was my $2,500 "barn Find".
Well after driving and having fun with it for a few years now, I've been going over the car in preparation to paint (back to original silver) and found this rotted section.






The A arm mount seems solid and the area by the tow loop/tie down seems solid. I realise I need to replace that section but how far should I go. Would it be best to replace the whole front section?



Thanks!

[ischmitz]

Looks like some major surgery is required. I would strip the underbody coating to access how bad the rust is. Chances are there is more.

[Jim Sims]

"Chances are there is more."

Like 100% probability; check rockers, fenders and cowling plus rear fender supports.

[Zeke]

That is a low lying area and is very prone to rust. Same with the longitudinals and the base of the A and B pillars (which you really can't see too well to investigate). What happens, usually, is rust flakes start to build up and soak up water like a sponge. The result is what you see. Now, the rust may be isolated to where the crud is/was, or it could be a lot more extensive. It really depends on how much acid was spilled into to the pan or if some salty water got forced in there.

Another hot spot is below and behind the strike plates on the door jamb. This occurs frequently for the same reason: Dirt gets thrown in there by the rear tire and cakes up. Next thing you know, there are some bubbles on the door sill. By the time you see that, the rust is fairly extensive in the concealed areas behind.

I hope this is not necessarily the situation in your case, but if it is, it's all repairable.

Cars I've worked on have had rust right up to a line and then clean metal above. If you were a little closer, we could go over the car and check out all the typical spots.