I was Changing the alternator on my 04 A6 S-line from underneath, when I went to put the belt back on I used a 1/2 inch breaker bar to loosen up the tensioner and as soon as I put a load on it it broke the 17mm head off. I can't figure out how to get it off? I can't get to it? Any suggestions?

 

Ouch.

You're going to have to most likely pull the lock carrier off and get at it with some type of extractor as a result. I wouldn't dare try and just force the belt on as the tensioner has now been compromised. Doing extensive work on my own 2.7, I can't see anyway of getting this done without really pulling the lock carrier off for access.

 

I got it.. Didn't realize it was just a 10mm Allen bolt holding it on. I managed to squeeze it out without taking the front off. Ordered a new one from NAPA, $66, will be here in the morning. But I bought a DAYCO belt and I know it's the right one (says Audi 2.7T on box) but before the tensioner broke it wasn't even close to fitting. Any suggestions on getting it on?

 

Ok, I didn't read your first post as closely as I should.

There is the mounting bolt which is an allen bolt that holds the tensioner to the block which you already removed. The other bolt (Which I believe is indeed 17mm as previously indicated) is actually attached to the housing of the tensioner. When you apply downward force (I think) it will allow the tensioner to pivot, thus giving you enough slack in the belt to slip it on, and then release pressure and it will take up any slack on the belt.

 

The tensioner should come with a pin installed that locks it in the loose position. Install tensioner to engine & install serpentine belt. Once belt is installed you can slightly turn the belt adjuster (17mm) & remove the locking pin. Then slowly relax the torque & the tensioner should tighten the belt.