Problem solved - lines were backwards I need to drive this Blazer to work tomorrow. I just installed a Cummins 4bt in my 78 Blazer. Put in Hyd boost brakes. Now I can't steer while pressing on the brakes. Also, if I saw the steering wheel back and forth while pumping the brakes, the pedal will drop to the floor sometimes. Steers great if I'm not pushing the brake pedal. I know I need to bleed my brakes more, but I didn't think that would affect the steering. What should I check? Does the hyd lines need purging somehow? Pump is gear driven, so no belt. Pump came on motor.