Although my car is a 400E when I had to place the water pump the service CD's called for the removal of that bolt, its tightened to 400nm, thats a almost 300 ft. lbs! The CD's said to get that special tool that mounts to the starter and locks the flywheel in place. Luckliy I just removed those 6 bolts to the pulley

__________________
1992 Mercedes-Benz 400E
2002 Mercedes-Benz ML500