There are some posts about how people have done this. Just thought I'd post mine. This is on my 1985 380SE. I removed the assembly from the back of the alternator. Removed two screws and popped it out - easy. Then had my "Oh S**" moment when I saw how fiddly it would be to put the new one in - to compress the brushes in particular. I tried tieing the brushes down with string, but at first couldn't compress them enough. Then I tried to fiddle it in with my fingers, no luck. So this farting around took about an hour. Then I tied the brushes down again, looping the string over the brushes and then around the outside (VR) side of the VR unit, and tying the string as tightly as I could. Then to make the string tighter I fiddled with it to go over the VR flanges. To make the string tight I think you could put some cardboard or pieces of popsicle stick to shim the string between the string and the unit body. The trick is to really compress those bad boy brushes down as far as they can go. With the string compressing the brushes virtually all the way down the unit went back in the alternator easily. Then I inserted and tightened the two mounting screws, cut the string and pulled it out using needle nose pliers.