Originally Posted by adantessr
It sounds like the booster is bad to me also. As already mentioned, a new booster W/O master cylinder should be less than $100.oo . First though, I would make sure that the vacuum check valve on the booster is opening. Just pull it out of the booster leaving the hose attached and make sure you are pulling vacuum. Let us know.
It should suck air with the engine on? I've already checked it and it was pulling air when I took it off the booster.