antivic

today i changed my rear pads, rotors, everything went fine, i "screwed" in rear caliper piston with the brake line disconnected, and it went smooth, i bleed the rear pass side and it grabs hard, good, i go to bleed the rear driver side and i go through almost a whole big bottle of brake fluid and get very little pressure, the ebrake holds but i don't know how strong it would be, but i can't move it with my hand on light pressure. i don't know whats wrong oO theres no leaks cause i spent a good amount of time looking...anyone had this prob before?