Contour Enthusiasts Group Archives Forums Modifications Aesthetics Aluminum Fuel Door No No

I don't know how many of you guys have done this mod yet but there is somthing you need to look out for. It is a corrosion caused when two dissimular metels are mated together with out any type of non-corrosive material between them. It is called galvanic corrosion. What it is is an attack of the two metals on each other. The sheet metel on your car will rust and the aluminum will "protect itself" by corroding, (aluminum does not rust but it will bubble and flake off to protect the good aluminum underneith). In order to prevent this you must put some kind of gasket between the two as well as using plastic washers around the nuts & bolts that hold them on. I work in a bodyshop & have had to change two of these same type of gas door on the new Eclipse. They come with a gasket but they have forgoten about the plastic washers. I'm sure many of you have actually seen galvanic corrision when you have taken an aluminum wheel off of a steel rotor and you have to hit the tire with a sledge hammer or something simmular. I haven't seen the kit from Ford but I would think It would come with a gasket. If not, take a jont down to your local hardware store and go back to the plumbing Isle. The hardware store should also have plastic washers & either aluminum, stailess steel (which won't harm aluminum), titanium, zinc plated or DARCO coated fasteners.

The Bullit mustang has steel fenders and an aluminum fuel door. That aluminum fuel door is what we are wanting to see fit on the Contour which also has steel fenders. I'm sure there is some type of gasket of separater between the door mounts and the painted surface of the fender.

It sounds like the metal you have been messing with is organic

All metals are organic. It is the combination of ores and the purification process, amungst other things, that give you different types of metal. What I'm saying is if you want the aluminum to stay looking nice and you don't want rust to form, do not allow the two metals (especially these two types) to contact each other or you will have problems.

No.

Organic or no...thanks for the heads up.

I don't know what your source is, but I highly doubt it's true. I have a aluminum mountain bike and I have quite a bit of steel (not stainless steel) parts on it. I don't have any problem with corrision. Mind you, the crank and chainring I've got are aluminum and the chain itself is steel.

The only real thing you need to look out for is titanium nuts and bolts (and screws) on titanium parts.

Strong,
Thanks for the warning on the fuel door mod. At the very least with this new info the mod can be researched and approached more carefully so that if ugly and damaging corrosion will be a problem it can be avoided now rather than trying to correct it later. At least you are trying to look out for us, and I can certainly appreciate that. Once again, thank you.

Well no problems with mine. The door isnt touching bare metal, there is a layer of paint and clear coat also the glue holding it on. So whats the problem?

Strong is right about the dissimilar metals. Working on aircraft for Boeing you need to have dissimilar metal protection if you are using another metal on the aluminum or the aluminum will start to corrode.

Basic explanation is right, but it does not apply here. Corrosion would be important if the rear fender was bare and exposed. So corrosion of the aluminum will be minimal unless there are some large bare metal zones in contact with the door (and large bare zones are bad enough as it is...

BTW, this principle can lead to much more trouble with the exhaust in road salt country (I shiver when i see a 304SS steel muffler welded to an aluminized pipe)