why does this always happen? I just bought a new caliper maybe a month ago and it's all rusted up, this also includes the rotor (the top of it is rusted up too)... I mean the car is driven every day, don't really see how it is rusting

 

The metal that the rotor is made of will rust whenever moisture touches it, same as the brake drums and pretty much everything underneath your car that isn't painted. If you leave your car parked for a few days, then the entire rotors will rust, but drive it down the street and they're clean again.

 

Is there any rotor that won't rust? Maybe brass or something?

 

Brembo has certain ones that are zinc coated and don't rust.

I have a theory that if you spray painted a new rotor with high temp paint then installed it the pad would only rub off the paint from the surface but the hat and the edge and stuff would still be black, black is better than rust. I noticed the new CLs have their rotors like that.

 

Yeah I thought about that.