I'm not sure what others have suggested yet but basically sounds like you have air in the lines and the best way to fix it is with two people.

You need to do this with the car "off" and the abs disconnected by removing the abs relay and fuse.
Have your friend, girlfriend, wife, kidnapped neighbor whatever apply the brake inside while one caliber at a time open the bleeder to allow the air out until you have a clear stream of fluid bleeding out. (you'll now because you'll hear air and start to see foamy fluid then clear fluid)

Air is compressible this is the problem, brake fluid is not although it does start to boil at certain points sometimes moisture can get in the lines too which is why it's very important to bleed off air which has moisture in it.