Depending on where you go, you might get away with it, but an expired passport is not valid for anything. Then again unless bouncers or bar staff clock the expiry date you should be alright with the birth date on it.
Tennent's would seem more than likely to do this. I've been ID'd everytime I've been in there, even with family. I guess that's just down to their normal clientele. Worth a shot though.
You'll get served in PJ Champs no bother.