Out for a short afternoon run on the PCH in the 67 SeriesI EType after a few miles of running at 60, temp up to 70degC, stop at light, try to get going and barely moves, after brief checks keep trying and with gas pedal down and creep along against much resistance to side of road. Car will not budge, nothing visible at wheels. Get out jack and if falls apart, put it together and for first time jack up car with original jack. Wheels froze, so figure a central brake problem. Get out lead hammer, tap master cylinder and power servo unit, lower hood, put hammer on seat, raise up and lo behold car moving down slope. So get it buttoned up and off I go to run errand pushing lightly on brakes, then home. Mash on pedal in garage, can not get brakes to lock again. Any thoughts? Thanks, Jay, Laguna Beach oh, guess good news for clutch, no slip