A6- How do I tension water pump/PS pump belt?

[Nj]

there's a twittering from the belt that goes across the PS pump and water pump. I had the tray off and car up on a lift while my mechanics and I tried to work out how you take up the slack on the buggr. any ideas? Looks either like there's a spring in the water pump that's gone and the whole pump need replaced or there's some kind of german witchcraft that means if I loosen it off and tighten it it will take up the slack. is that possible? I'm stumped and don't want to balls anything up by just having a go with no knowledge
cheers


Also getting vibration between 65mph and 75mph. just had 4 new tyres and tracking done. I'm wondering if they balanced one of the wheels badly.

[Knight Rider S4]

Noel while i remember save this link for your car

http://www.audidiy.com/c5a6.html

http://audi-sport.net/vb/showthread.php?t=34262

[Nj]

cheers Steve. I've been doing a fair bit of reading there. Still haven't picked up on whether the pulley on the water pump is self tensioning. There doesn't seem to be any other way to manually tension so looks like i'll have to try loosening it off and tightening up. Otherwise i'll assume it needs a new water pump. I need to pull teh cash together to get the garage to do the timing belt soon anyway so I might be as well getting them to replace the water pump at the same time anyway.
Any thoughts?