No sure what part you mean, I have a diagram of front suspension but it's to large for me to post. PM me your email address and I send it.
ron

Edited:
I think there are only two ball joints on each side of the front, the bottom, hard to get out and the top which on other MB cars was sold as a unit with what was called the upper control arm. In other words you just replaced the whole upper control arm.

Diagram can be viewed here:
http://www.msnusers.com/mkorrmm3g8rpsh6mhio79l4bn7/Documents/ml%20suspen.jpg