84 full size. Stepped on the brakes today and the pedal was hard. Truck did stop but why the hard pedal I'm thinking?! On the power brake booster is a check valve. Connected to that is a rubber hose that goes to the rear of the carb. In between is another valve, a round size barrel shape about 4 inches in diameter and a few inches long with male fittings at each end, one fitting is "L" shaped. My question; is this valve a two way or one way valve? I can blow air through both ends and suck air through both ends. I'm thinking, why have a valve if air coes through both ends. So, is the valve bad? What about the check valve on the booster itself? One way? Or is the power booster given out!? What is the name of the valve between the booster and the carb? What can I do to improvise until I get the correct parts? Thanks!