Apologies in advance for reviving this thread
A little background.
Long story short I thought I had a leak of the VC where oil was traveling down onto the downpipe. After receiving the parts and tearing them into the car, it was found that the oil leak was actually coming from the supply line to the boost solenoid. I found this thread and a few more and thought I found the Hail Mary with the nipple/diaphragm replacement mentioned above. Although the car ran flawlessly after cleaning out the chamber and all lines the issue quickly returned after driving for about 30 minutes. A new valve cover is on order, and I am hoping that remedies the issue (being an internal crack and oil being sucked into the vacuum chamber). I have DIY'd just about everything on my car and do my best to follow all service bulletins and procedures as they are available online, needless to say, I am not ready to replace the vacuum pump yet as I am preparing to do the rod bearings, timing chain/guides and eccentric shaft/bearings. I came across this video today and thought it would be a good addition and help with future issues others might come across.
http://www.youtube.com/watch?v=ZHYP6oK-gTM&t=918s
I replaced the VC about 20k miles ago with a Bavarian Motorsports cover from ECS Tuning and have been chasing a boost leak for a while, got tired of it after buying a smoke tester, upgraded Turbo inlet, and a few other things, and ended up wrapping all charge connections with Aircraft Pressure tape and thought that would surely remedy the issue. (it did for a while) I think now it is either the valve cover or the vacuum pump. I also have slight surging at low speeds (no pedal input). This went away after changing the nipple connection, though. I wish there was a way to test the vacuum pump itself. Any guidance is greatly appreciated.