"Power Bleeder" is preferred...(Do a Search,you can make one from a sprayer)
BECAUSE,you will not risk running out of Brake Fluid.
AND it's a one man 10 minute job!
Two chambers to the Master Cylinder Reservoir ...The Back Chamber FILLS by
overflow from the Filled Front Chamber.'Really hard to see except with a light
shining on the Reservoir and viewed from the Passenger side!
I suspect that you ran out of fluid,hence the "Pedal to the Floor" symptom.
Here are the Official Instructions:
http://www.ps2cho.net/downloads/MB%20CD/W124/w124CD2/Program/Chassis/42-0010.pdf