Hello just installed the power disc brake conversion kit on my 69 camaro and am having troubles. I bench bled the master, installed the kit filled the resevor bled the brakes starting at the rear drums made my way to the front. Got all the air out I believe. The rear drums I had to rebuild because the cylinders were blown out. The front brakes work just fine. The emergency brake works. When I depress the brakes and check the rear they still spin. I adjusted the shoes as far as they can go. I watch the cylinders and both do not move. How can you adjust the proportioning valve to allow more pressure to the rear or does it sound like a defective valve? Also my booster,master and prop valve all came assembled.