My '74 has been sitting since 1991 and after freeing two of the brakes that were sticking I took the poor stripped down beast for a couple of trips around the neighbourhood and found that the brakes don't feel quite the same as they did before I put the car away. They need more brake pedal pressure to do the job. What would be the cause? Would a worn out power brake booster be the culprit or maybe the air hose from the booster to the intake manifold has a leak although I checked it and it looks old but seems to be okay. Or maybe the calipers themselves? Is there a test that can be performed on the booster to see if it's okay?