What is this tool for?
 

This tool is part of the original toolkit in my car. I was hoping someone would be able to tell me what it's use is?

It's the one which is out of the case at the top:
http://i26.photobucket.com/albums/c1...3/DSC00083.jpg

helping you put wheels back on the car

Yup - stud setter

So, I screw this into the hub and put the wheel over it?

Makes sense as the last time I changed a flat it was very difficult to put the wheel back on due to the weird reverse stud/bolt arrangement

Now THAT'S a tool I could really use! Anyone know where I could Buy one...anyone have a spare they would part with?

The tool is available from the dealership. However, the fact that it's in the tool roll suggests that a previous owner used it to change a tire. The factory location for the pin is in one of the lug holes of the spare, held in place by a black foam donut.

Search ebay for mercedes tools; there were some available recently.

They're not available as a separate part, only as part of the tool kit, which is expensive. Figure out the threads and you can buy the bolt and cut off the head.

For the 12mm bolts
Part No. A126 403 00 74

1264030074 MSRP $3.50 Core $0.00 Online Pricing $3.15

Sourcing a long enough bolt, cutting it . . . worth $3.50 for an MB part?

Great if available. A parts guy told me it wasn't - might be.

+1!

Take a lug bolt into a fastener store and for a couple of bucks you'll have a nice long (3" or so) bolt that can be cut to be this tool. BTDT, have two.

Having accumulated many of these tools, I'm pretty certain that the foam donut in the lug hole of the wheel is a 201 thing or maybe a later model thing. 123,126, 124 all come in the tool wrap.

As far as the 201 chassis I have one that I picked up which is not the stamdard length as shown in the OP picture but is about half that length, came out of a spare tire lug whole with a donut it's just much shorter!

Baloney.

This tool is nothing to get exiticed about, as it's less than $10 at a dealer and consequently fervent internet searches, making your own, etc., are a waste of time.

Yep

I bought onr for each car a couple of years ago, but, after I tried using the tool, I found that it was easier just to manhandle the wheel into place the old fashioned way.

It was actually your dealership there in Albuquerque that told me it wasn't available as a separate part. But as I indicated earlier parts guys aren't always right.