Lee,
I believe that your drawing is correct now that I look at it and a couple others.... Not having car to stick my head in and look is the pits!
I always thought that the pressure port was at the end.....not the middle! Like brake M/C. But I guess if that end port is blocked off during the piston stroke, you won't have fluid going up into the reservoir! Seems backwards....... but I found other drawings showing similar with reservoirs at end port!
Brainfart!
Cheers!