I was driving the other day when my (drum) brakes locked on, i pulled to the side of the road but the brakes were too hot. I let them sit for a while (40mins) and checked them again, somehow they had unstuck themselves. To make a long story short, the master cylinder had a blockage in the return valve, i got it machined and put it back on, i bled the brakes but the pedal will not come all the way up. The brakes only start to grab right down the bottom about an inch from the floor. Does anyone know anything about this. I need help!