AFTER BEING DRIVEN 50 MILES THE CAR WAS PARKED ON A SLOPE OF 6 INCHES IN 24 FEET. THE PARKING BRAKE WAS SET AND THE MANUAL TRANSMISSION WAS IN NEUTRAL. AFTER 2 HOURS THE CAR ROLLED BACKWARDS 75 YARDS, OVER A SMALL TREE AND STEEL FENCE POST AND CAME TO REST IN A FIELD OF TALL GRASS. DAMAGE TO THE REAR BUMPER WAS SUBSTANTIAL. CLOSER INVESTIGATION REVELED THAT EVEN THO THE PARKING BRAKE WAS SET THE CAR WOULD ROLL. IT APPEARS THAT AFTER THE BRAKES COOLED OFF FOR SEVERAL HOURS THEY RELEASED THE PRESSURE AGAINST THE REAR BRAKE DRUMS AND ALLOWED THE CAR TO ROLL EVEN THO THE SLOPE WAS VERY SLIGHT. THE ISSUE IS THAT EVEN THO THE PARKING BRAKE APPEARS TO BE SET IT WILL ALLOW THE CAR TO ROLL AFTER THE REAR BRAKES COOL AND RELEASE THE SHOES FROM THE DRUMS.*AK