bighands

So I'm doing some preventive maintenance yesterday and see some rotted vacuum hoses at the vacuum actuator. To get to the bottom hoses on the actuator, I take out the two torx bolts and slighty slide it forward, and I hear a 'click'. Now the actuator won't go back into the plenum all the way. On top of that, I ruined the plastic tips on the plastic end diaphrams. So now I need to 1) replace the vacuum actuator and 2) figure out how to service it. Bentley shows an exploded view of the MFI, specificall the Intake manifold change-over system components, but no procedure for servicing the vacuum actuator. I've looked pretty exhaustively on this site, and others, without luck. Anybody ever serviced one? It looks like the plenum may need to be removed, but I'd rather service it in place if possible.
Thanks,
Jim

bighands

Ok, here's the followup. The vacuum actuator is connected to the intake manifold change-over mechanism. Of course it's a dealer-only item, and I got rooked. The cost for the actuator, change-over cylinder, intake manifold gaskets, replacement injector o-rings, and 6' of vacuum tubing was a whopping $650. So my learning lessons are:#1 Be very gentle when pulling old tubing off of plastic connectors, slice it open lengthwise with a very sharp cutter first, and #2 Some items aren't servicable even if they look to be. I posted a pick of the work in progress. Note, I did go to the Audi dealer and was able to speak with a tech, which was invaluable. I found it helps to be very humble, know what you are talking about, and be conscious of the time to ask questions.
The car now runs great, and I actually found a few other vacuum lines that were rotted.<ul><li><a href="http://pictureposter.audiworld.com/117534/a6.jpg">http://pictureposter.audiworld.com/117534/a6.jpg</a</li></ul>

wiinky

A few days ago I found a frayed/broken vacuum line at the same location, just before the vacuum actuator (see link below). Was hoping that the old line can be replaced without removing the actuator. Do you have any more words of advice for that procedure?<ul><li><a href="https://forums.audiworld.com/a4/msgs/2762636.phtml">https://forums.audiworld.com/a4/msgs/2762636.phtml</a</li></ul>