There is an easy way to do this on a 500, but you have to get the right tools. You will need a 12mm allen wrench and some inverted torx (on some of them).

You can take off the belt and then the pulley. (You may also want to take off some of the plastic around the distributor cap area for access>)

Next take off the small connector hose that is below the reservoir but above the pump (you will replace this hose).

Next you will remove the hoses that connect to the pump body then the 4 13mm headed bolts on the pump body.

DO THIS CAREFULLY AND HOLD ON TIGHTLY.

CAREFULLY slide the body from the rear portion leaving it on the car's engine.

You can now install the seals and reassemble the same way.

Good luck.

This is NOT how the manual says to do it, but it WILL work and will save you countless hours.

__________________
Benzmac:
Donnie Drummonds
ASE CERTIFIED MASTER AUTO TECHNICIAN
MERCEDES SPECIALIST 11 YRS