I replaced the water pump on my 84 back in 2007. It just recently started to leak again. I noticed when putting the new one back on that the larger bolt at the bottom which goes on last and goes over the alternator bracket doesn't cinch down tightly. About a millimeter of play in it. Is there supposed to be a washer under the bolt? Perhaps that was the reason for the leak. Obviously there has to be some play in it so that the alternator bracket will swivel to some degree when adjusting the belt, but I don't think it should be as loose as it is. Or perhaps there is crud inside the engine threads.
It just seems like a strange design for Toyota. Either the 2 bolts on either side of that larger bolt are enough to keep the water pump mounted tightly and there is no passage for coolant around the looser larger bolt or the bolt should be torqued down tightly and thereby not allow the alternator bracket to swivel at the lower end.
Any ideas?