Good luck with the warranty claim. My buddy at the stealership said that they are indeed an alloy. If that's the case then unless you apply a surface treatment and then stop stepping on them, the problem will return. He states that they use Aerospace to maintaint the handfull on the lot.

If BMW doesn't make this right and/or some of you want to tackle this problem yourselves, I think the dogs balls solution would be to have the boards anodized. Anodizing is available in pretty much any color you want and will solve the rust issue.

Incidentally, aluminum can rust, but cannot have rust. Rust used as a verb is synonymous with corrosion or oxidation. Rust used as a noun refers to the oxidation of iron.

i have the same problem with my running boards and are forever coming out with these rust spots like a 15 year old with acne. i have found that a good alloy wheel cleaner does the trick.yet im not sure what this does for the future condition of the running boards.kind of like breast implants....makes it look good but could be bad news in the future.

Jeremy, I agree.

spenburge :lmao:

had the same problem, i work at a dealership and i went to the detail bay, we have this blue chemical...kinda like windex but a deeper blue.
sprayed and left on for 1 min, used a wash cloth and it came rigth off
i dont know what that blue stuff is called right now

is there a way to find out the name of this "secret" solution?:confused:

ill find it out, cause i tried looking for the name, and how we get the solutions/car soap and all that is in these huge barrels...ill ask the detail guy for the name of it, cause it sure works perfect!

OK when I said rust I meant corrosion in general. I didn't mean to start a debate about what rust is and how aluminum can't rust. The fact is they are corroding/rusting. I don't think it is 100% aluminum. The corrosion spots are definitely sunk into the metal and not just appearing on top. It is also reddish brown like rust that you get on iron/steel.

I am having them replaced under warranty at the dealership today.

I tried using an alloy wheel cleaner called Wonder Wheels that works really well on the alloy wheels, but it only took away the worst of it and it was still noticeble. They tried to clean them the first time I took the car in, but you could still see pinhead sized spots all over. I'm also not sure what effect this has on any protective finish these boards have and fear that harse cleaning materials could only exacerbate the problem.

I'll try putting some kind of hard wax or some other type of water repellant on it the new ones and see how that goes, because I think it is formed when droplets of water lie in one place on them for a while.

As I said the used car sales manager at the local dealership (where I work as well) admitted that this is a known problem and they get it frequently and it is usually covered under warranty. I will need to check under what warranty it is covered though and what period it covers.

Are these aluminum boards extruded, or just a thin skin of Al sheet on a plastic frame?

Either way, if the metal not anodized, why not get them anodized?
You won't be able to polish them highly, but highly polished Al will always corrode in where corrosive elements and moisture are allowed to contact it.

I work with aluminium alloys on a day to day basis, and I can safely say that very few products are made from pure Aluminium (Al) alone, most are alloys containing small amounts of Sillicone (Si), Magnesium (Mg), Copper (Cu), Manganese (Mn), Zinc (Zn), etc.. like this extrusion alloy that could well be used for running boards http://www.comalco.com/freedom.aspx?pid=524

I'm no expert on conductivity or corrosion, but is it possible that there is some sort of reaction that occurs between the (aluminum) running boards and the zinc-coated sub frame? And in some climates this process is accellerated? I'm thinking along the line of diodes that are placed on outdrives or keels in a marine environment....just thinking out loud.