What kind of easyout did you use . If its the taperd sguare type and if you can still see some of the bolt around it then you can use a pointed type chisel used for exhaust pipes and such to chisel the end of the broken bolt away . As you chisel the bolt it will loosen the taperd easy out. I know this might sound stupid but it has worked for me . You really have to be able to see what you are doing. Try to use a magnifier to actually see if the easyout is in the center of the bolt. You can also make one of these chisels out of a center punch by grinding one side only down to the point so as to gouge the metal out around the easyout. I have also used the method of welding the nut to the broken bolt which works well. Because the bolt is flush with the machined surface (more or less) you have to be careful. If you can get the broken bolt out and the threads are messed up you can always use the helicoil or even possibly tap to a larger bolt size and drill out the water pump bolt hole. Hope this helps. Larry