Good evening,I am new to the forum and have a few questions regarding a 1986 chevy van (305, 4-barrel carb) which I recently purchased for 500 dollars with the understanding that the transmission was toast. I am not too concerned about that since the 700r4 transmission is not very expensive to rebuild locally. So my issue i as follows... I dropped a battery in the ole girl today and she fired right up the first time. The motor was idling great till i applied the brakes to see if there was any pressure, next thing I know the engine idle drops and finally it stalled out. Well as soon as i turned the key she turned right over and was idling smoothly, so it tried the brakes again and the same thing happened. Now this may be a stupid question but i am not familiar with older vehicles. My stalling issue is due to either a vacuum line leaking, or even a failing diaphragm in brake booster, right?