Got a problem with the mighty GeorgeCo E30, driver's side rear brake: During the July Driver's school, the piston seized and I wore the pads to the backing plates and destroyed the rotor. I replaced the caliper and flushed the fluid. I thought the problem was that the piston was retracting. Now I have a new (rebuilt) caliper and still have very rapid wear on the pads, but only on the left side. The car only has a couple of hundred miles and one track day since the new caliper was put on. The pads on the right and both fronts look almost new. The rear left were down to 2 mm remaining. What's next in line to check? Look at the hard lines running the length of the car to see if they are somehow damaged? Is there some sort of left/right proportioning valve that's not working (I thought that was only front/rear)? I didn't notice anything unusual under heavy braking, it just must not be completely retracting each time I brake. I'm not sure what to check next. Thoughts?