dskippy888

Hi fellas, been lurking around here for a while. This is my first post! Someone from a BMW forum referred me to rennlist for all my 928 inquiries.

1) Does anyone know whether Mothers Mag & Aluminum Polish is safe for the stock rims for an 86.5 928S?

I read on the back it says that it should not be used for "painted or coated surfaces", but I am not sure whether our wheels are painted.

2) Basically, my problem is that the front rims are stained black. I cannot scrub or clean it off, and I have even tried Meguiar's wheel cleaner. Does anyone know how it got stained like this?

ShawnSmith

The "flat dish" wheels were painted from the factory. Over the 20+ years, many have been re-finished, either with different paint, chrome, or just a high polish on the aluminum. No idea what you've got there. Suggest pulling one off, cleaning an area not visible from the front, and testing on it.

dskippy888

Well I am the first owner of the car so I am sure they have never been re-finished.

So, given they are in this stock condition, do you think it is safe?

ShawnSmith

Sorry - I mis-understood the scope of no-idea-how-they-became-black.

If these are stock original wheels, then they should have paint on them, and the aggressive polishes may remove said paint. At a minimum, I'd go gentle until you find out if the black is heavy brake dust deposts onto the paint, or some other problem such as the paint flaking off.

Marine Blue

Have you tried a paint polish?

I've been thinking about using Mothers Yellow Paint Polish Ball with a paint polish on wheels, maybe this would work for your wheels...

dskippy888

Hmm... perhaps I will try get some pics up to give a better idea of the black stains. It just looks dirty more than anything, it doesn't appear to be chipped of flaked at all.

I have heard some people using those Mr. Clean magic eraser which serves as an extremely mild polish to get brake dust off, but not quite sure whether it will be effective in this case.

Charley B

Well Skippy, it appears you are saying you have owned the car since 1986 and the wheels came from the factory the way the are.

So, use a good stage one paint cleaner, then polish and then wax.

dskippy888

Yup, 22 years of ownership and I love it more each time I look at it. I find myself driving it far more in the summer than the new cars in my garage!

As for the wheels, are the products you have suggested just the same ones that one uses for the paint on the body of the car?

Charley B

Right. Meguiar's comes to mind, but there are several good products that include a paint cleaner as a first step. Because it sounds like the wheels are painted, it's important not to use a general purpose cleaner as they tend to be rough on paint. If there is a build up of brake dust and grime you should be safe with a gentle washing with Dawn dish soap to soften up the hard stuff.

Marine Blue

Try Meguiars Scratch X, should work well and bring back a nice shine.

Where are you located?

dskippy888

I am located in Canada.

I saw Scratch X at the hardware store, I will try pick some up and do a clean when the weather gets a bit better. Thank you all for your helpful suggestions, I will be sure to update on the results.

pcar928fan

I thought all the flat dish wheels were anodized... I don't think I have personally seen a painted flat dish. I have seen polished, chromed, and ruined (because of an acid based cleaner) but not painted. D90's...painted, etc.

heinrich

I have owned over 20 928's and never seen painted flat dish wheels. From the factory, I have seen only chromed; anodised or untreated bare aluminium.

dr bob

What Jim said... The flats came anodized from the factory. Some came with an additional platinum layer that made them darker. None were painted or chromed from the factory but some were chromed by the dealers prior to original sale.


Back to the problem at hand--

The black that shows up on the wheels is typically the result of someone polishing them in the past but not maintaining the polished surfaces. The original anodized layer pretects the base metal (aluminum) from oxidizing, but once that layer is polished or eaten off by chemicals, the raw aluminum quickly oxidizes to a dark grey and then maybe black over time. The new oxide layer actually protects the aluminum underneath. If you rub with a soft towel and your Mothers Mag and Aluminum Polish (the stuff in the little jar...) and come up with black on your towel, you're on the right track. A jar of that polish and a 5-gallon bucket of elbow grease will get your wheels looking pretty good. You are also a candidate for using a power tool to do the big grunt parts, but power tools also risk damage so I'll leave that option to you to decide.

Most spray-on mag wheel cleaners that say not to use them on painted surfaces are acids that will strip off the outer layer of oxide. The flats on the 928 seem to get streaks from that stuff. PO's detailer used it once and couldn't get it off quick enough to avoid the streaks. Took me a solid day of hand polishing to get them halfway decent looking, but at the same time the original satin sheen of the anodizing was gone. I still have the anodizing, but it's a bit closer to semi-gloss now. Moral-- stay away from the spray-on acid wheel cleaners unless it's the first step in an extended recovery effort that doesn't include keeping the anodizing.

There are services that will restore your original wheels. In the US, Wheel Enhancement offers this service. Guys at 928 International use a local service that does some pretty amazing work on these restorations. They look better than I remember then looking from the factory. There are also folks on the list here who might be able to offer some replacements in better condition, for a fraction of what a full professional restoration will cost.

SharkSkin

Are you sure that's not just 22 years of brake dust?