I had this happen on my wifes SL320. I know this will sound kind of hoaky but I actually fixed it with "baling wire" (actually some regular mechaics wire was what it was. I don't have any pictures but I used the wire to tie the broken parts back together on the motor. It has been three years and still works like a champ!! No Vibration!!
I have slept many times since then so things are not real clear but I did it with the blower in the car. Which was a little tricky but if your patient and have a long nose pair of pliers it can be done.