[RogerD]

Other than a couple of bubbles at the ends of the rockers, my 72 Spider seems pretty "rust free." I did a thorough PPI up on a lift and didn't find anything scary. So I was shocked when, during a recent tank rehab project, I reached up under the fenders inside the trunk and felt rust. There is no evidence of this from the outside. Using my digital camera instead of trying to stand on my head I saw all kinds of rust on these surfaces, under the rearmost trunk lip, inside the "tops" of the fenders, over the wheel wells. The worst was a spot on the left side of the panel between the rear of the passenger area and the front of the trunk opening. I still need to figure out how water gets to that point and address that.

I hit everything as far as I could reach with a wire brush and POR15, with the results shown.

Obviously I can't reach every area with rust, but I think I did what I could. Would it be a dumb idea to just spray rustoleum back into the area above and forward of the wheel wells? I'm reluctant to just let fly since I have a nice paint job and don't want overspray coming out some place. Any thoughts on that?

 

[bianchi2]

..hope this helps a little ..on the 3 rd. photo,, i would get a shop vac, and chip/clean that area really well...then go to your local hardware store.. i saw some rest treatment in a large spray bottle..kind of like a '409' bottle.. and spray like crazy to get that rust..if you could get a wire brush up there that would help... but after you spray the rust converter , get some rustolium epoxy paint or por and coat it really well, the por will work in the areas you can reach, but where you cannot reach..use the epoxy paint, and spray the entire area..

 

[jjb]

Roger,
the rust you are showing is pretty common I think even when the car looks great from the outside. Mine certainly has it. After searching quite a bit on the internet, it looked to me like a strong school of thought is that periodic treatment with an inhibiting oil is pretty successful.
I use ACF-50 and Corrosion-X. They are both available from
www.aircraftspruce.com (see airframe components and then search)
in liquid and spray form. I take an undercoat sprayer from Eastwood and blast the whole inside structure (through the grill, wheel wells, etc.) as in the pics below. It won't hurt the paint, I was just too lazy to wash the car afterwards, so I covered it. Car should "drool" the stuff after you're done. See the before and after pics below. You can do this with nothing but a cheap garden sprayer too. You want to "fog" it as much as possible.
Another key thing to do is remove your door sill trim's sheet metal screws (the stainless strip at the bottom of the door opening) and seat belt bolts. This gives access to the inside of the box section of the sill structure. You can then take one of the spray cans of ACF-50 or Corrosion-X, which has a tube on it like WD-40, insert it into the holes and spray all around as best you can.

My $.02 worth.

Cheers,
Jeff

 

[Zunige]

Roger,
I am no rust expert, but you may want to take your car into a shop and ask then for an opinion, as this seems to be a bit more than just some surface rust... I am also wondering if your rear drains are fully open, or if your trunk gasket needs replacement...

Best regards,

 

[hjm]

For my cars back home I have used Mike Sanders Korrosionsschutzfett which is applied hot (good warm)
It was rated by a German classic car magazin as the best stuff on the market after some longterm and demanding tests! I has worked for me!
HJM

 

[RogerD]

Thanks for all the suggestions and recommendations. As I said, I've already hit all the rust I could reach with POR15 after knocking it down with a wire brush. That seemed to take care of everything I could reach. For the large surfaces, such as the insides of fenders I have to beleive that the source of water would be condensation hanging on the surface. Obviously it's not coming through from the outside. So coating the surface should protect against further corrosion. The trunk gasket seems OK; pliable, no chunks missing.
Enrique: Not sure where the rear drains are to check.
On the worst rust spot (which the one shot shows "after" being chipped down and POR15'd) the water might be coming in through the hardtop attachment brackets, or through tiny cracks in the triangular depression outboard of the hinge. So I need to hunt that down. I think I'll try to get some epoxy rustoleum back into the fenders where the brush won't reach, and that's a great idea to treat the inner sills through the trim screw holes.