Hi, I need to know if I put say 30 psi into the booster at the vacuum port should it hold the air? I am thinking it should but I would like other opinions. Thanks

 

???
And why would you? It's designed to produce vacuum, not hold air pressure. And do you know how much air pressure it would take to blow out the diaphragm or other parts?

 

Sorry to get picky RAD, but the booster doesn't produce vacuum, the engine does, the booster uses the vacuum to help you press on the brakes. I am sure you know that but just to keep from confusing some of the newbies...
PC, why in the world would you want to pressurize a vacuum booster? Since it is designed to hold the atmosphere out (a vacuum inside) it is not designed to withstand 30 pounds per square inch trying to get out. picture how many square inches we are talking about and realize that that is a whole lot of force. Don't do it!

 

OOPS, yes, that is correct; I meant it acts on vacuum not on pressure.

 

Like they said it's not designed to withstand any pressure, it has a one way valve to prevent that sort of stress.

 

Not sure why you want to but,
I, for one, want to see the attempt.
Take video.

 

To answer the OP`s question
NO it will not and you have now ruined it .

Then maybe that is the plan??