The MB manual says to remove the ign. lock which is a PITA. To get the clearance to pull it out you will need to remove the tumbler, then get to the set pin which holds the lock in the column....

I changed mine a few weeks ago without doing anything to the lock. Using a shorty phillips head screwdriver (about 2 1/2" long) I was able to remove the two screws which hold the valve to the ign. lock. I removed the lowerdash panel and laid on the seat to get at it, not fun!