Probably some Saturday Warrior overtorqued it, possibly overtensioned the belt too. Maybe that weakened the bolt. Whatever the case, I just got the car running. Cured an overheating problem by changing the water pump. 2nd one I've ever done. Makes me a Saturday warrior myself....but it went smoothly. I'm proud.

Even though it is far easier than timing chain driven pumps, I feel like I can do almost anything in this car now. That said, I am going to a machinist to get that bolt out. I really don't want to even try the whole drilling thing. I believe it cracked while driving, as the pump was intermittantly working when the car last ran, in retrospect, one bolt was holding it in which was enough to make it work, but under a load (with the wheel cranked all the way) the pump would flex and the belt would spin causing no fluid to be pumped, I know this because when I was dissasselbling things to get at the water pump, I noticed that the steering pump was sort of flopping around in there. So the bolt must have cracked a while back. It took me a bit to piece this together, as I thought the bolt was just really short when I pulled it off...but yeah, that is why the thing was loose.