This makes me very afraid to take out my bins. -_-
Hopefully it's not horrid.

 

The water gets in through a couple of small holes in the wheel well. They're higher up near the shock mount. Mazda must have used the holes for some manufacturing procedure. Look at the wheel well from the outside and you should be able to find the holes. The problem is there are actually two layers of sheet metal here. An inner that you can see when you remove the storage bin, and an outer which is exposed to the wheel well. The water comes in through the holes that are suprisingly poorly sealed and sits between the two sheet metal layers. If you see rust when you remove the bin, it's already rusted through this inner layer of sheet metal. Just sprayin rust-x or whatever on the rust that you see isn't really protecting anything.

 

ok, here's my question, how can we stop this from happening? My car has some minor rust in the compartments. Would it be a simple matter of plugging those holes you mention? or is it more complicated than that? As far as I know my rust won't require whole new wells in order to correct the problem, but eventually it will if left untouched.

 

plug the holes with JB Weld. Get some rust removing jelley from auto parts store and squirt it on the rust. the directions say to wash off but I don't like putting more water on a rust area so I just grind the used rust jelley **** off. Reapply as needed. Clean with acetone or brake cleaner. Primer. Paint.

-bp-

 

I would, but JB Weld doesn't come in gallon buckets, nor does it take well to sculpting large curves.

My clean, bought from original owner, 76,000 mile 85 GS was driven through several salty Michigan winters by that original owner.
If I end up keeping that unibody (which I wasn't planning on) I'd have to do the big setzep transplant. It's that bad.
There's worse: you should see the parts heap I'm stripping. You can almost crawl into the car through the driver's side rear wheel well.

 

If you take the bins out and see rust, you have rust BETWEEN the two layers. If you just put the rust jelly on the rust you see you're not protecting anything. The rust between the layers will continue to grow. If you see rust in there and you want to get rid of it, you have to remove the inner layer sheet metal, treat the rust on the outer layer if it's not too bad and weld a new inner layer into place. You have to get between the two layers to treat the rust. If you do cut away at the inner layer, you'll probably find the rust is MUCH worse than you thought.

 

My thoughts exactly.

 

This is why this particular rust is such a curse, it's not an easy quick fix. It's a hidden internal cancer that MUST be cut out and then replaced, which requires metal working resources.
Surface rust is a cinch, but this is not.

 

Yep rust sucks. I can almost pick a hole right through my wheel well. I'm just going to cut and weld it all out. And if I can't find a clean parts car. I'll just weld some boxy style well's on as its a racecar.

 

My LE has a hole the size of a water mellon on the driver side. I hope I don't find a nasty surprise when I look at the S more closely, argh what a pain.

 

Listen to this guy guys. He's 100% right. I've said it many times but I'll say it again. These cars rust from the inside out...Period. If you see rust trust me you can't fix it by simply sanding and re painting. If I knew then what I know now (before I got my car pictured a page back) I'd just hold off getting a FB untill I could stumble across that perfect rust free desert car.

 

I'd hate to be the one to say it, but even if it has quarter sized rust spots on the inner well, it's probably very rusty underneath the surface

 

Fiberglass is your friend.

 

Probably, the S is got enough compartment rust that its crumbling apart and there are pieces of rust laying in the bottom of the car. hmmmm, wish i knew how to weld.... Here's an idea, what if I cut out the inner layer of metal, get rid of the majority of rust on teh outer layer or metal, treat it with something like por15 then just lay fiberglass on the inside to take the place of the inner layer. *could* that possible work? Or am I way off?

 

I think that ought to work. Maybe someone already did this....anyone?

 

guess there's only one way to find out...