I have never had this problem. The only bit I can offer is to SLOWLY and EASILY squeeze the lever (rapid pumping will create small bubbles that are very difficult to bleed out!) to get the big bubbles to float up in the reservior or down thru the bleed screws. I have the one-way valves on my bleed screws (Dual Star parts) so it's a tad different in how I perform that bit. Sorry I don't have a full method for ya.