as you all know most audi's with R134a only has a high side service port.
DennisStehlik has a little how to on how to make a hose that would work for the shade tree guys..
for the others that are not inclined to do so or would rather take it to a shop that only knows high and low side charging, you can purchase these little doo-dads on ebay.
item # 4578802735<img src="http://i7.ebayimg.com/02/i/04/e7/2d/8c_1_b.JPG">

item # 7624674320
<img src="http://i16.ebayimg.com/01/i/07/45/5b/74_1.JPG">


They will convert audi's 1/2" female acme connector under the low side pressure switch to a standard low side port so any R134a hose and guage set will work, even the crappy do it yourself recharge kits with the plastic hose fittings.<ul><li><a href="http://forums.audiworld.com/a6100/msgs/58748.phtml">DennisStehlik how to</a></li></ul>

What a "cool" find. Way to go to v b chil-n for finding this, and to whoever is making this. For under $12 I got a set to try out and see how it works. Looks like it will work just like the contraption I put together, but much more gracefully. Small enough to leave in the car just in case I need to do some 'quick' repairs while on the road.

Ha..you got me laughing out loud v b chil-m... thanks for being so kind in calling me a "shade tree guy". I would say I am inspired by the desire/necessity of avoiding my Audi dealer at all costs. The last time I took the car into the dealer was to get the AC system recharged. It came out in worse shape than when it went in. When I took it back they took it for an hour..said they ran a check on the AC system again and that it was performing to specifications (ie..temp drop at the vent outlet) which was not true. I just didn't have it in me to fight with them over it more, so I set off to figur out how to recharge myself (and to be able to look at low and high temps while the system is running to check performance). Has worked great ever since and have not had to recharge again since.

Else you are just asking for trouble. Have heard of people destroying their compressors by overcharging...and that would be very expensive and a pain in the @$$ to fix.

Is the thread going to fit? I know that the thread on low side safety switch is 12 mm fine. Can someone confirm this?

yes the threads fit and it has a schrader valve so you don't lose freon. even audi has to follow standards when it comes to A/C fittings they just make it more difficult for us guys and other shops to do the work, so you have to go to the dealer..

the correct term for the A/C fitting
is 1/2 inch acme which is also the size of the yellow hose on most guage sets..

<center><img src="http://www.jcwhitney.com/wcsstore/jcwhitney/images/imagecache/G_21385G_SW_1.jpg"></center><p>I looked at the how-to you linked to and it's a little more than I want to get in to, but it sounds like you're saying all I need is a can of refrigerant with a gauge like the one pictured above and I can recharge the AC just like I do on my older Audis?

If so, that's probably the best thing I've read on the forums in the past year!

I think audi charges by weight so the right way is to discharge then recharge with the correct weight of freon

How would one go about evacuating the system first? Is this required? My A4 is just 10 years old and is blowing warm air, and this seems a whole lot more economical than taking it to a dealer for $200.

if its empty then you could buy a vacuum pump and see if it holds a vacuum
or take it to a local shop and have them vacuum it for you
either way its cheaper than the dealer

So it's definitely something I have to do before using a self-recharge kit?

Thanks so much for your help man. I ordered those parts via eBay, and as soon as they get here I'm going to get one of those cheap r134a kits at walmart and see if it works! I'll post my results!