I have a 71 Nova with 4 wheel manual drum brakes. They work, but the pedal goes to the floor. I pulled the lines from the master cylinder and plugged them to test it. Pedal was firm. That's not it. I then pulled each drum and had someone press the brake to see it the cylinders were working and they were. Brake shoes look fairly new. I put back on the drums and adjusted the shoes properly. Next I bled the entire system until the fluid coming through was clean. Everything went fine except that no matter how many times I bled the passenger front I was getting air bubbles. The lines and hoses all look to be in good shape and fairly new. I see no leaks and the master cylinder has never needed to be filled. Anybody have any ideas? If there was air in the line I thought pumping the pedal would bring the pedal back up. Also the car doesn't pull to one side. If there was air I thought it would. Thanks for any help.