Same sort of thing happened to me last night. My brakes were doing their usual constant scratching and squeeling noises, but much worse this time. I could smell the front driver's side. When I got home, I pulled into the garage. Front driver's side assembly was just radiating, it was so hot and smelled. But the other side seemed just find. I drove around in a circle slowly and had my g/f stand outside the car to see what was making the most noise. It turns out it was my rear brakes. But they don't heat up cray like the front's do. This was odd, because in no way at all was I even using them that much. I had 4 people in my car, and we were just casually driving about 15km, then the brakes just started to go nuts. I also noticed my balljoint (which will be replaced soon) was making much more noise than usual, and my car would shake occasionally at only 60kph+. My tires have so many clip and sht on them from attempted balancing, it's impossible to fix.