Disc brake rotor rust


#1

I have this recurring problem with the formation of rust on both of my Subaru’s brake rotors. Obviously there is nothing I can apply to the disc surface to prevent this, so I’m frequently cleaning them with Scotch-Brite. What causes this? Is it just cheap rotors and are there better quality rotors out there that don’t rust. Both cars have aftermarket rotors installed by Midas (gulp) unfortunately.


#2

“Both cars have aftermarket rotors installed by Midas (gulp) unfortunately.”

Okay, so now we have one more reason for NOT using Midas!

Seriously, however, the rust is worn off the rotors after one or two stops, and is not likely to harm anything. Yes, it is likely to come back in a day or two if you live in humid conditions, but it is really more of an esthetic problem than anything else. I suggest that you stop using Scotch-Brite pads on them, and I strongly suggest that you stop using Midas–unless you relish being overcharged for substandard parts and labor. They also have a tendency to tell you that you need repairs that are actually not necessary.


#3

All disc brake rotors rust, and rust quickly. You will typically see rust on rotors after only a few day of non-use. This is harmless. It is best ignored.


#4

There is such a thing as rotors that are more rust resistant than others. It depends on what the rotor alloy is made of. For example, I understand that a few years ago as a cost cutting measure, GM eliminated the chromium in their rotors which increased rusting (this article makes reference to this). Unfortunately, I don’t know enough to recommend a rotor that is rust resistant.


#5

My VW’s rotors do not rust; never have. The VW has been stored in the same garage that I store another car whose rotors do rust.


#6

There apparently is no iron in your rotors or there is no moisture in the air in which you live.

Brake rotors are made of ferrous metal and they rust. Period. If you drive it often enough, the rotors will stay clean and you might not notice.


#7

Some performance rotors are plated so they resist rusting outside the pad swept area.