My evo has 43k miles (all stock) on it and it has started snowing here. I notice that sometimes the brakes will grind. Similar to if you wash the car and a little oxidation builds up on the rotor. It only does it sometimes... very random. I would think if the pads were wore down that it would be consistant.

It sometimes does it when I first drive.. it sometimes does it 20 minutes in.. I went ahead and bought new brake pads. Going to examin the pads to see if thats the issue but, usually it will squeek first letting you know they are low and I never heard a squeek.

Any other ideas?

Yeah, on an Evo, the only way to learn the condition of the brakes is to pull the wheels and look. Sometimes the pads wear unevenly meaning the noise maker isn't always the first metal to hit the rotor.

ABS activating can sound like brakes grinding.

Had the bolt back out and made a loose caliper on a car before that caused a similar problem.

Rust, forget about it.