testing brake power booster off the car

[Seppi72]

I know how to check for a weak power booster that's on a working car and there are many videos on how to do that.

I have several boosters from various cars that I've amassed and want to know how many, if any of them are still functional before I go to the trouble of refreshing one or more of them for my restomod.

• What I'd like to know is if there's a way to determine the "goodness" of a power booster that is off the car.

I have a vacuum pump, tubing and gauges and figure that I could draw an 18" (or so) vacuum, shut the pump off and then watch the vacuum drop over time.  I could do the same with the installed and working booster on my other S30 to establish a baseline.

Does this make sense to those of you who might be familiar with this?  Or, is there another way to make such a determination?

[Patcon]

I believe you will have to make a way to seal one or both sides of the booster to hold vacuum...

[Captain Obvious]

If the booster is in good shape, it should hold vacuum. You'll need to put a check valve (or manual shut-off valve) on the vacuum source side so you don't lose vacuum back-flowing through the vacuum pump when you turn it off, but other than that, the can should be sealed.