Massive leak at fuel filter

This is my 2006 (I know this is the A4 spot, but it is a PD and you guys are more into maintanence that the A5 spot). I seem to be really stupid about changing this new style fuel filter. I first changed it at the 20K interval. It was fine for a day, then it started leaking. Badly. Lost 1/4 tank in 10 miles before I noticed. Took it apart and it seemed fine. I reseated the filter and had no leaks. About 200 miles later the same thing happened. I took it in to the stealership and the couldn't find anything wrong.

I just got done doing the 40K service and was very careful about the filter. I drove it about 20 miles. No leaks. Today my wife called me and said it was leaking really badly again. I just followed the trail of diesel. She lost 1/2 tank in 15 miles. I reseated the gaskets. No leak. I drove it home and again no leaks. But now I am really hesitant to send my wife back out.

How could changing a filter be so hard? I just took out the old element, fitted the new one back in and tightned down the screws in a pattern like you change a tire. The center pedestal is spring loaded and is compressed when you tighten it, right? Are you supposed to not push the element all the way to the bottom?

This has me pretty frustrated. I'm pretty handy and have done all my own maintanence on all the cars I have owned.

Anyone out there that can tell me how I am messing up?

Assuming you have the new style A5 filter (metal NOT plastic top and bottom of the filter element) I can't think of anything that would cause a massive leak besides rolling the O-ring that seals the top of the cansiter.

Where on the fuel filter is the leak coming from?

Yes, it is the new style. The gasket seemed ok, but it is inside the canister, not on the cap when you take it off, so it is hard to see if it had rolled.
I'm starting to think the cap is warped. I'll check it tomorrow.

So far, so good. I must have pulled up some before tightening it down and rolled the gasket.

Did you replace the goofy green gasket? New filters should come with a new gasket. At least, the 3 or 4 I have done on A5 TDIs came with them.

You really ought to go over to the A5 forum. There are detailed instructions on how to do this correctly. You probably have not got the oring around the cap done correctly. Search over there for the thread. If it is leaking from the canister, and you didn't remove the hoses, it has to be the lid oring isn't sealing properly.

Here is one:

http://forums.tdiclub.com/showthread.php?t=175046&highlight=fuel+filter

Pay attention to post #8 second picture and the green oring around the cap.

Yes, I did seat it right, BUT I think I rolled the gasket by pushing down before I started the screws. Then let it come back up only on one side.
Anyway, it is fine now. Thanks for your help.