2005 CLK 500, 178,000 miles, Searched threads and posts and didn't find info as to alternator installation help so this may be helpful for others who need to replace the alternator:
a) The alternator can be removed and installed from the front and up and out, but it takes a lot of wiggle and a few beers
b) DISCONNECT THE NEGATIVE BATTERY CABLE!
c) From the bottom of the car, remove the plastic large engine pan and then from the alternator disconnect the electrical connector and the large B+ cable with the nut
d)Disconnect upper radiator hose and pull the fan up and out
e)Disconnect the water pump hose ( it goes down and is in front of the alternator)
f) Remove the ban that holds the reservoir hose to the side of the frame and work that ban out of it's hole.
g) de-tension the serpentine belt
h) remove bottom mounting bolt of the alternator and then the top
i) tap the mounting bolt sleeves outward so the installation of the new alternator is easier
j) remove old/install new ~~~ beer break !
h) Torque B+ bolt 16 Nm, Torque mounting bolts 33 ft lbs
i) put all the stuff back together again; reconnect negative battery cable with the headlights on.
j) turn off lights, start car, check for 14+ volts across battery terminals; YES. Good to go.

It took me six hours to figure it all out and had to add a gallon + of anti freeze to top that system off. Good Luck!