help, the ball and chain said fix it or sell it!!! not a chance. i have completly changed the brake system.pads,shoes.master,booster,calipars,cylinders,rotors,drums.the pedel feels like i am driving a model T.. they are very weak and hard. i have bled them till iam blue in the face. all the parts came from auto zone.could it be the proportioning valve???dave how much vacume shoold be at the booster???