I've never had to bench bleed a Mercedes MC. But I've occasionally run into problems because there are front/rear chambers molded into to reservoir...one can run dry, but not the other. So now when I bleed the system, I keep the reservoir full to the brim. When I'm done bleeding, I use my Mityvac to remove enough fluid to get it to the fill line. Others may suggest a power bleeder. Also, be sure you start with the right rear, then left rear, right front, left front.