im having issues getting to the rear o2 sensor on my 1.8T i cant seem to get in a good position to get a wrench or socket on it and have the leverage to break it free.

im wondering what you guys have done to get at this lil bastard i allrdy wired up the universal sensor to the old wire and plug

 

I just did this a few weeks ago. I couldn't get it from above or below so i took the front wheel off and got to it from the side. There's a some kind of guard or heat shield that your probably need to remove if you do it the same way.

 

I haven't tried to do it on this car so I can't offer too much advice but be sure to have some Aerokroil or Silikroil (or, at the very least, PB Blaster - but the other two are much better) and soak it hours (at least) in advance. Also, don't use a cheap socket. I've rounded off sensors from trying crappy cheap sockets and now I use a good old Snap On socket.

 

is this the precat O2 you are referring to?

if not ill have to look into it more i wouldnt think taking the wheel out of the way would afford a better vantage point to work on it

 

I'm thinking you may need the offset O2 sensor socket like this one (not sure about the size though):
http://www.sears.com/shc/s/p_10153_1...5&blockType=G5

Does anyone know what size O2 sensor socket is needed for the 1997 A4 1.8T? I was ordering some new "toys" (pickle fork set, etc...) from Sears and wanted to get the O2 sensor socket(s) I'd need while I'm ordering - that's what brought me to this thread.

Also have a 2001 A6 4.2, if you know what size O2 sensor socket it takes I'll get that one too. - Thanks

 

Yeah from putting a clutch in a 1.8T recently we learned that the secondary O2 doesnt look fun at all. Removing the exhaust seemed easier than getting at it in place lol. See about using a bunch of extensions and going across the top of the tranny from the driver side. It may not work but look at it - had to do an S4 that way.