I've had a problem for awhile now of poor braking. It wasn't too bad just had to push on the pedal a little harder then when I first bought the car. Did a lot of things to try and fix them, but here's the real problem.
The right hand stem of the booster check valve was broken off, it should be much longer, the hose was barely on there. The previous owner had tried to glued it on. I got that whole line from the junkyard and that one had the same broken stem. I replaced the vacuum line from the intake to the brake booster, including a new check valve and now the brakes are beautiful. The A/C works a lot better now too. I think the hose that connects to that stem probably goes to an HVAC vent somewhere. I'm thinking my heat will also work much better too. Happy Days!