Aluminum running boards rust problem.
 

X5 4.8is. Reg March 2005.

Has anyone else experienced this?

Small spots of rust starts forming all over the surface of the entire running board (looks like chicken pox). The spots gradually gets bigger and bigger and it doesn't look very good.

One of the guys at the local dealer stated "off the record" that this is a "known problem" and his "demo is only a few months old and it's the same" . (after I bought mine of course!!!)

Now it is still covered under warranty and I'm getting mine replaced soon, but what happens when warranty expires?

Surely BMW has to do something about this to prevent it from happening. I don't see the running boards as a consumable (like tyres, filters, etc) so I don't expect to need to change it every 6 months.

How long are the warranty on these boards?

I'm sure that those of you with the running boards can seal them some how to prevent this.

I've had mine for 6 months and have had no problems. Aluminum doesn't rust, it oxidizes but aluminum oxide is white. Could the discoloration be mildew or similar? Is it humid in the UK most of the time?

The only possible way of avoiding these rust marks, is to clean these boards very frequently, certainly in the winter (salt etc). I clean my boards and wheels almost every 4 days in the winter. In the summer, just once a month. No marks at all. But I know they tend to form rust marks very quickly. I also doubt that these boards are 100 % aluminium.

I`m in the UK and I have the same problem. I only noticed it this weekend when I was cleaning it. I only installed mine 3 months ago and I`m not too impressed. I need to call in to the garage so I`ll have a word.

Just an idea, but if the boards are in aluminium, they cannot rust. What it could be is metalic particles that are abundant on the road (could also be from your own brakes)and which will get stuck on your paint and possibly on your running boards. They usually start rusting very quickly and give the appearance that whatever surface is rusting. My advice... try using a clay bar and clay lubricant, which is the best way to remove those fine metallic particles.

Sounds logical to me, If I get time, I`ll see if I can make sense of this over the weekend.

The bad news is that aluminum WILL RUST! The good news is that the rust closes out the aluminum surface protecting it from further rust, but then the additional bad news is that it not very cosmetically appealing.

I have an ALL aluminum Airstream travel trailer which has a special clear coat covering it. Where the clear coat is compromised it will start to corrode (just another word for rust/oxidation) exibiting as a white-ish raised area. Unless the running boards have been protected by some type of clear coat you will constantly have to keep them waxed or use some metal polish to control the corrosion.

I posted the same problem in another thread recently. Someone has since said to me that the running boards are probably an aluminium alloy. If they could be got off the vehicle easily and separated from the plastic 'studs' which protrude through the metal, then the boards could be repolished and relacquered.
I don't know if anyone has ever done this or if the boards can be separated so I'm going to try some metal cleaner in the meantime.
I have a feeling that BMW didn't use a very durable lacquer when they made these boards. Whether or not this is universally recognised by BMW as a warranty replaceable item will be interesting to find out.

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.