I recently bought a 2000 748S. It´s a great bike but the first day I had it, the rear brake went to sh#t. The bleedout valve came off and the pads rubbed until the disk went red hot and all of the internal gaskets fried from the heat. I replaced the rear caliper and bled the lines to get rid of the air. Seemed to work fine at first but again the pads started to rub, the disk went hot and the rear brake locked up. I was stuck in the moddle of the road until it cooled down and I could get the brake working again. Does anyone have any ideas as to what could casue this? The reservior is full of DOT4 fluid, the brake seems to work correctly, the master cylinder works and the disk doesn´t appear to be warped. ?????? Help!