Brakes causing stalling

[Mountaineerfan 44]

So I’m going to be tracking down some vacuum leak today. I know what to check, but I have a question for the knowledgeable folks here that have helped me in the past! When driving yesterday, the engine would sputter and want to die when I stepped on the brakes at a stoplight. I’m going to check the booster and check valve, and I admit I’m not fully versed on how power brake systems work, so what is happening with the power brakes that would cause engine sputtering?

[Brian Conway 264]

Where does the booster get it's vacuum from ?  Should be the intake manifold and not the carb.  Brian

[Mountaineerfan 44]

Yes, it’s from the manifold. I’m just curious as to HOW it works, from an academic standpoint. 
BTW, I’m pulling good vacuum (17-19” at idle), and I can’t replicate what happened yesterday (of course).

[LoneWolf2U 136]

possible leak in booster.

Run engine to build booster pressure and shut it off.

pump brakes 3-4 times to relieve build up. With foot on brake start engine, does the pedal drop down? yes the booster is working.

No the booster may be leaking internally.

Also after running engine listen for leak at booster check valve.

[Dave R. 85]

There are several good youtube videos on how the boosters work. One is a younger guy with a drawing of a booster using a white board. Another is a guy in a wrecking yard and at a point he cuts a booster open. Both were very informative for me as I battled brake problems last summer.  The guys at Power Brake Booster Exchange  in Oregon are great also.   Dave R.

[Mountaineerfan 44]

Thanks!

By the way, my vacuum problem wasn’t a vacuum problem. Pretty sure I had water in the gas! It’s purring after filling up again, using a water treatment, and putting in a new filter.