Hi guys, I am in process of reassembling my car.....anyways, I'm cleaning the exterior surface of my booster and decide to suck on the vacuum nipple (yeah, I know, weird fetish) because I assume it should be airtight.
Well, I can suck on it as if it is vented to atmosphere - can't blow into it though.
Is this right?
I had no reason to believe there is an issue with the booster, since the power brakes worked fine when I parked the car 2 years ago.
Thanks for any info.

The valve on a brake booster is a one way valve........when you blew on the valve and couldn't get any air thru it....its only designed for one way travel.

As far as trying to suck on valve and get any results, I doubt this test will yield any scientific results. Not enough vacuum. You could try to use a running vehicle, tap into its vacuum system and then test the booster to see if you hear any leaks. Just a thought!