I'm actually in the same boat. I am in need to replace the damper and tried without removing the pully but to no avail. You will need to remove the fan blade and clutch and pulley to better get to it.
I now there is a tool from MB to my recollection made for this application as the bolt tha tholds the fan in place is a torx type? No room for a regular socket and ratchet as you are in the radiator and risk to damage the radiator.
If anyone has completed this task if they could post more details of how to get this task completed.
