I have a 91 325iC 147K miles.the rear disc brakes start to make a dragging noise at @ 20 mph. this is w/o having applied the brakes. when this happens I just touch the pedal and it goes away, but does come back.
ghead I have replaced 1 rear caliper that was bad, the other looked ok inside. I have replaced brake lines and took apart the brake regulator valve and cleaned it and of course new fluid and flushed the system very well. I still have this noise and ALOT of rear brake dust on both wheels , 2 to3 times more dust than I am getting on the front brakes. The excessive dust has been a problem for a couple of years, also just installed new rear factory pads, and they are getting ate up also.
Any help would be appreciated. I'm think a master cylinder is bad but don't know how to check it