I have a vacuum tester, not mityvac brand. In need to pull a vacuum on my brake booster as i suspect it to be my "no vacuum shutoff" culprit. If i run the car without driving it, or touching the brake pedal, it will shut down. Also after very short trips it will shut down. If its anything more than a short jaunt, or if i use the brake, it wont shut down. I pulled the main vacuum line out of the brake booster and plugged it with my thumb then ran the car, it shut down....
SO...
1) How can i hook up my vacuum tester directly to the brake booster? does the mityvac brand have a fitting that my brand didnt come with?
2)Has anyone else had brake booster related vacuum issues?

Did you pull the main vacuum line to the booster and then plug the end of that line and your engine quit running...If you did then I am confused as why this would indicate you have a vacuum leak in the booster....this indicates your vacuum leak is somewhere else...I think...I might be wrong...Jim

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James A. Harris

Attach the vacuum tester to the main vacuum tube (The long black one).

Remove the other vacuum connections from the main line and plug One connector, attach the tester to the other connector and try to get as much vasuum as you can. Keep in mind that the brake booster is large and it may take awhile to get any vacuum inside it. Get it to 15" vacuum and leave it there. If it stays at 15" for 3 minutes+ it's fine.

While you have it connected to the main line, start the engine and see how much vacuum the vacuum pump creates.

If i have the tester set up the way you describe, and i apply vacuum, it leaks slowly. I also had someone apply the brake pedal while i had the tester set up like this, when it was applied i lost all the vacuum. Is this normal?

There is also a check valve at the vacuum pump that could leak. I have never changed a brake booster, but it sounds like it is your problem. Search the scrapyards/pull-a-part yards first, you could likely get it for pennies.

When i go to the Pick-n-pull, id like to be able to test the brake booster. I'll need a way to hook up my vac tester directly to the BB...I know it can be done, i remember seeing someone post about it here...for some reason, my brain is telling me it was Gottadiesel, but i dont know. Ill continue searching, please pipe up if you have any ideas!!