Last idea to help with re assembly, find a piece of plate and drill a hole in each end to suit the holes either side of the broken one. When refitting the water pump, fit the plate and just before you tighten the two bolts holding the new plate, slide the spring washer in between the plate and the hole with the broken bolt. Then tension the two bolts either side, and there will be enough pressure applied where the bolt was by the spring washer and plate flex to do the same job as the original bolt. Use BlueMax sealer too, and you'll b fine! :)

