I think you got the idea on how to identify the botls but more importantly, be careful about the grade (strenght) of the bolt you are using. If is best to just to your local MB dealer and get the correct bolt for you application. Using a lower grade bolt might cause it to break in your application and then it just multiplies the problems you experience. I know this might sound like overkill and I too do things in a temporary fashion until I can get a proper fasterner, but just some friendly advice from the audience.

Wayne Hyde