vacuum leak narrow down to booster pump

[baba4444]

Hello All,
I have had a vacuum leak for couple days now, since the mechanic changed my brake master cyclinder. after so much investigation, I found out that is comming from brake booster (exactly where he changed the brake master). what could have been damaged or unpluged inside the booster?

any hint is welcome.

[Whiskeydan]

How deep is a hole???




Anyone?

[toomany MBZ]

There is an "O" ring or two involved.

[tangofox007]

There should be a rubber seal at the base of the master cylinder, under the flange where the m/c meets the booster. Most likely, it's either not installed or it got pinched. Or the m/c is not tight to the booster.