I'm pretty new to owning a W215, and I just ordered two new rear Thrust Arms for my vehicle, I was going to change them today thinking it would be a easy DIY, but when I looked at the bolts I was surprised to see a bolt style I do not have and from what I have gathered it is a Mercedes Speciality Tool, And I called a few different Mercedes dealers near by and they said ask service then service said ask parts, and parts said they do not sell these Speciality Tools. So now I'm lost at how Mercedes won't sell the tools but I did call as many stores as I could and came up with nothing. I then searched every Mercedes forum I knew of to see if anyone has done this to their vehicle but it seems somehow that I am the first and only... lol. But I did find a tool that looks like it would correct but I am going to visit the Service Dept. at my local Dealer tomorrow to confirm it's the correct part. The site I found the part from is http://www.pelicanparts.com/catalog/...CED-detail.htm and here is the picture of the tool, I believe to be the correct one. If any of you guys have any info on this it would be great, thanks everyone!

 

From wikipedia: http://en.wikipedia.org/wiki/Triple_square

 

Oh wait nevermind you need the male side. I presume it's just a 12-point torx bit? You should be able to find those at tool stores... Harbor Freight, Napa Auto, etc.

EDIT: nevermind what the heck am I thinking, triple square is the male side. Napa Auto should have that.