I feel dumb even asking this question. I replaced my rear brake line with one solid piece of stainless tubing, all the way from the proportioning valve to the rear rubber line. I just cant seem to bleed the damn thing. I`ve checked and double checked, there are no leaks. Went at it for more than two hours today, pumped a gallon and a half of brake fluid through the line. It comes out crystal clear, but every second or third pump, I`ll get an air bubble. Anyone have any tricks for getting air out of the high spots of the line? The bleeder screw on the proportioning valve is too rusted to even attmpt. I know its not bound up, you get pressure in the line with no brake light, crack a bleeder, pedal goes to floor proportioning valve cycles over, light goes on. Close the bleeder, pump the pedal, light goes out and plenty of pressure for the next bleed. I`m ready to hook the rear up to my towtruck lift it eight feet in the air and try again. If anyone has had similar problems with an airbound rear line, I`d appreciate any advice.