I would greatly appreciate any help I can get on this problem. Driver side front and passenger side rear brakes work together. I was having brake problems and pulled some of the lines apart. After everything was back together, the passenger front and driver rear bleed fine. I get nothing but air through the other two. I even went as far as to unhook the line from the anti-lock brake unit that travels back to the master cylinder. When my helper pumped the brake, only air came through the line. I never got fluid. How do I get this flow working again?