What did I break and what is it going to cost me?

[danewilson77]

I don't think you broke anything. I found this ebay listing so you can see what the part looks like:

http://www.ebay.com/itm/e46-Front-St...p2047675.l2557

Those are just splined studs that are pressed in to the shock mount. I found this on a Google image search so you can see what one looks like:

http://www.evocorse.com/en/colonnett...aggio-435.html

In the picture of your car it looks like the stud is pretty far down in the bolt so I think as you were loosening it it pushed itself down until the splines were out of the mount and then it just spins. With the tire off you should be able to get a long screwdriver up in there and tap it up so the splined part is back in the mount. To do this safely though you're going to have to get it up on a jack stand.

William.

Yup. That's them. Nice find on the pics. Once the mechanic get it started...and those splines are drawn up a bit....he should be able to thread the self locking nut the rest of the way on.

[wsmeyer]

Now that I think about it some more I would try removing the other two bolts and use a piece of wood to pry up the aluminum end of the strut brace. It shouldn't take much to get the splines to bite and then tightening the bolt would pull it back up into place.

William.

[LivesNearCostco]

I had this happen to me when I first tried to change strut mounts. A stud fell out. Best case you just push it back up so the splines bite, as said above. Middle case the stud falls down into the wheel well when you remove the nut. Worst case is replacement stud won't stay in and you need a new strut mount, which is not expensive, but changing the strut mount means pulling the strut out and using a spring compressor.

One trick to try if you still want to remove the nut is use a pair of needle nose pliers to lift up the nut while you unscrew it with the 13mm socket. That might let the splines bite enough to finish removing the nut. But then after that there's still the risk the stud will fall out if you tap it by accident. This is kind of like what WSmeyer suggested.

[Go Horns!]

Strut mount was busted. Ordered a new one. Hope to be up and running by this weekend.