It sounds to me like this is just normal oxidization of your rotors. As they sit without use a thin layer of oxidization builds up (slowly in the dry, but faster if the humidity is high) and then when you drive the car the sound you hear is your pads scrubbing this off.

Hot rotors don't oxidize so you don't see this if you drive frequently and it will change depending on the time of year and weather in your area. You may also find that your brakes are a little more "grabby" until this layer is scrubbed off.

I've always wondered why this doesn't happen from factory but I've just assumed that they apply something to rotors to keep them looking good while they are sitting in showrooms or in dealer lots waiting to be sold.


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I get a rubbing sound, every time, when applying the brakes; very noticeable at slow speed just before stopping.

This is not likely to be your problem, but I've found that the rear brakes are quite prone to getting small rocks thrown up into the caliper, and they will scrape in there until removed. The way to kick them out seems to be to drive in reverse and hit the brakes. Do it several times, and if rocks are in there they will likely eject.

I often have to do this after drives on freshly resealed roads or gravel roads. Might be worth a try to see if it helps.

 

Canux, I was inclined to think it was something else; thinking the rotors couldn't possibly oxidize that quickly, but the humidity here dropped unexpectedly recently and the problem disappeared. It occurred to me that the rubbing started with the onset of hot muggy weather and I don't drive every day. I can fix that. Thanks for the input.

 

The rotors will oxidize immediately if they get wet.

Rocks can also make a rubbing sound.

 

It's oxidation (rust) that develops on the rotors. I find it particularly annoying after I've washed the car and let it sit for some time before driving off. :wall:

 

Like Spencer said, they oxidized immediately. After I finish washing my car, they're already oxidized. Completely. Quite annoying. But they've never oxidized after washing the car here in the dry TX desert.