Broken Bolt in Water Pump

What every you do, once you are able to turn the bolt, turn it by hand, and when it binds, turn it back in some, keep working it back and forth. I had one of those top bolts bind up and put an air rachet on it and snapped it right off in the block. Had to take off timing cover and drill it out. Luckily I got it out without messing up the block. Sealer on the threads keeps the coolant out and keeps rust from forming.