Noise while wheels are turning? Mechanics, help?

My 2002 Lancer (same model as 1997, only facelifted) makes a rather scary noise while moving. It kinda sounds like the rubber is rubbing against steel or something. Or maybe like the brakes of a bus. I'm about 95% sure it's the right front tire (disc brake assembly, if that helps).

It's very unpredictable when it comes or what prompts the sound, but when it comes, it's loudest when the car's just rolling at a a few kph, and it grows fainter as the car accelerates, and is completely gone by about 60kph. also, the sound goes away while turning (i found this out by wiggling the steering wheel on a straight, doing about 20kph) and while stepping on the brakes. let go of the brakes and the sound comes right back. and then the sound mysteriously just stops while you're driving.

My dad's trusted mechanic has tried changing the brake pads, overhauling the brake assembly and a complete underbody wash, and nothing's worked. his next suspect is that the disc needs to be re-faced. I'm not convinced that the brakes are the problem since the noise actually stops when i hit the brakes. and since the guy's failed to stop the sqeaking noise of my dad's Honda CRV while braking, i'm beginning to think that brakes are his waterloo. what do you guys think is the problem? if you need more info, i'll update this question. thanks much!!!