brake booster help

[troy destroy]

ok. well just finished hooking up my booster and running new brake lines. got it bled and everything is working... except when i step on the brake pedal it wont return. you have to pull it back out. any ideas? they work great, its just the pedal. i am running the booster off the vacuum line on the front of the carb because there wasnt an outlet on the manifold. could that be the problem? i checked and there is a decent vacuum from the port.

thanks in advance for any help