Hi, you cannot effectively flush the ABC system on your car without Star Diagnosis to actuate the struts in rodeo mode. I recommend you don't even attempt this repair as there is a very good chance that you will damage the power steering pump. The flushing routine should be done by a Mercedes shop with the Star Diagnosis tester.
If air enters the system during the flushing procedure you can ruin a very expensive power steering pump in a few minutes time.
I can post the workshop procedure if you'd like me to but without Star Diagnosis you cannot purge the system.
Click here for the workshop procedure.
Let me know if you have any questions and please remember to click Accept so I receive credit for my help.
Well since I've already phurchased the pump not sure which route to take at this point.
You're taking a big chance trying to flush the system yourself. If you want to try it you need to make sure that the fluid never runs low in the reservoir and it draws air.
You still won't be able to perform the rodeo activation to purge the shocks however.