Thanks, but I don't understand what you are suggesting. If you mean give the master cylinder piston a full stroke then this is what happens now with it connected to the pedal. The master cylinder piston is returning hard up against the circlip at the end of the cylinder. This appears to be the actual stop for the pedal. At this point the inlet port should be uncovered, allowing free movement of fluid to or from the reservoir.
107.023: 350SLC, 3-speed auto, icon gold, parchment MBtex (sold 2012 after 29 years ownership).
107.026: 500SLC, 4-speed auto, thistle green, green velour.
124.090: 300TE, 4-speed auto, arctic white, cream-beige MBtex.
201.028: 190E 2.3 Sportline, 5-speed manual, arctic white, blue leather.
201.028: 190E 2.3, 4-speed auto, blue-black, grey MBtex.
201.034: 190E 2.3-16, 5-speed manual, blue-black, black leather.