Hot Rims and Cast Iron

[ZEDohSIX]

I regularly detail my Corvette Z06 chrome rims with Hot Rims wheel cleaner. My brake Calipers are painted and they also come up well.

However the bare metal cast iron caliper mounts end up with a white coating that I have never been able to remove. I recently detailed a brand new Mazda RX8 and an identical thing happened on first usage to that cars bare metal cast iron caliper mounts.

What is this white coating on the cast iron, how do I remove it, and should I be using some other wheel cleaner?

[Teak]

What have you tried to remove the corrosion? What other wheel cleaners have you tried?

I would clean, prep and paint the bracket for easier cleaning and cleaner apparence. Another thing I would try is a metal polish to restore the mounting bracket.

Eric

[ZEDohSIX]

So far I have tried NXT car wash and a detail brush, and some Vinyl and Rubber spray (which I find surprisingly useful in removing lots of unusual things) with a toothbrush. Neither even hinted at budging the white marks.

Note that this doesn't look to me like normal corrosion - there is no obvious pitting though both surfaces are quite textured - it looks more like a coating that perhaps is just below the surface. It happened very quickly (ie: 30s) and subsequent uses of Hot Rims don't seem to have any further effect.

Painting the brackets might work for my car but isn't going to work for the second car I detailed which is not mine. I plan at some stage to use Brake Cleaner to see if that removes it. I will also try the metal polish but don't expect much due to the texturing of the surface.

Any further advice is welcomed.

[ZEDohSIX]

A further update: the white coating on the RX8 seems to fade over time and subsequent use of Hot Rims does not cause it is re-appear.

Could it be a residue from the manufacturing process that has reacted?

[Mike Phillips]

Hi ZEDohSIX

Welcome to Meguiar's Online!

I'll forward the link to this thread to Tom MacDonald and Mike Pennington and see if they can add some insight to this issue...

[Mike Phillips]

Mike Pennington got back to me on this and said that at this time the best and safest thing to do is to wash with only soap and water or use our M36 Hi Tech Wheel Cleaner as it is acid-free.


#36 Hi-Tech Wheel Cleaner




Also, you might like to read this article...

ADR Design Wheels Tests and Recommends Meguiar's #36 Wheel Cleaner

[MB///HRV]

My first guess is that the the white you are seeing is some sort of flash oxidation that is ocurring when the wheel cleaner gets in the pores of the cast iron. Similar to what happens when an acidic cleaner is used on non-clear coated aluminum wheels. You may want to be sure that the calipers are cooled down before spraying the cleaner and also to thoroughly rinse off the cast iron portion immediatly after being sprayed. Perhaps the reason it hasn't been occurring recently is because the pores have had time to fill with dirt/grease/oils etc and the cleaner isn't penetrating the pores.