Yeah clutch hydraulics are funny stuff. Couple weeks ago it took me over an hour to bleed out a wilwood 1" master and a CNC billet slave. The damn MC just would NOT pump any fluid, regardless of either of the bleeders.. and theres so little fluid volume you really do have to crack that bleeder and close it as quick as you can before the pressure drops or its going to take it back in..even if you have a catch can, the bubbles are so tiny they dont just float out.