Wait...weld small piece of metal back to the frame? Details. Also, if the water pump cover is cracked, that can just be replaced. If the block where the water pump cover mounts is broken, then you have bigger issues. Get some better, lighted pics of the damage and we can help more. Welding frames is serious business. If you have a crack in the frame you have a big issue. How fast were you going when you laid it down?