Loosen the pump bolts a couple of turns and wobble the housing up and down- - - -that's plenty of movement to get a vacuum reading. It's too bad common sense isn't an off-the-shelf item at a parts store.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!