Saw your other note. I have a brake booster, believe it's good but can't guarantee because I haven't used it. I wouldn't sell it, but I'd trade it if you eventually gave me back a good one, assuming mine is good. Maybe that's not a lot of help to you.
Jon Norman sells rebuilt ones, but they're expensive. I would send it to Karp's in LA, Upland I think, for rebuild. I had them to a VW ATE booster, $175, very good.
You try APE? I'm sure they have some, whether they test them I don't know.