91 civic stock bb and mc, when the car is idling i can hear a pretty big air leak coming from the bottom of the mc and bb. If i poke my finger around I can hear the sound change. What exactly do I need to replace to fix the leak? I'd prefer not to have to replace everything if I don't have to but I also cant seem to find any sort of gasket that's mean to go there either. Also I don't have any problems braking or anything like that.

 

There is only a single vacuum hose that runs to the booster. Check it to see if it has split or cracked.
If it is in good condition, the your booster is leaking. The only way to fix that is to replace it.

You might be able to unbolt the MC and remove the booster without having to open the hydraulic lines, but I'm doubtful that is actually possible.... Just wishful thinking probably.

The booster clips to the brake pedal with just one pin. It is then held to the firewall with 4 nuts under the dash. They are accessed from under the dash - 2 are really easy to get at and the other two will likely have you wishing you never owned a car.