abhartach

Someone along the way installed power brakes on my !956. I recently bought this 63,000 mile car, and I'm trying to fix some of the problems that came with it. The unit is a Bendix, and it looks original, but perhaps not 1956. I've looked closely at the system since one of the problems I'm having is that the power brakes work initially, but quickly go to manual. I've located a bad check valve, and there was a leak at the carb T coming from the fuel pump. Using a vacuum gauge I found that I had 18 inches of vacuum that disappeared as soon as I shut off the motor. This led me to the check valve. I was fortunate to find a new one. I've installed it, but haven't gone any further. My first question is did 1956 have a single pipe connection at the Treadle Vac and a T elsewhere? I have 2 hose connections that appear to be merely a T at the unit itself. I was told this is 1955. Also, I have a valve that is operated off of the brake light switch, and it's installed in front of the reserve tank. I was told that this was used earlier, but not in 1956. Perhaps unnecessary? I realize that the Treadle Vac was used on a lot of other cars too, but since my tow board, pedal, etc. are correct, I'm thinking that this was taken from an Oldsmobile. Can anyone clear this up for me?