Hello about a year and a half ago the plastic impeller inside my water pump blew and I had to replace it. That was fine but since then I have had to install three more. Not because the impeller blew but because the pump gets a leak underneath the pulley. Oh Ya, I have a 1997 Four Contour LX with a Duratec V6 engine.

The leak happens from underneath the pulley on the front of the water pump, I originally thought that it may have been the seal but it was not. I have moved the battery and let the car run and you can see this clearly. First I thought that it was just a bad pump but now this is the third time that it has happened.
I noticed the first time that I fixed the problem that shaft to the impeller seemed to be bent, and the other one I changed quickly before anything could happen. And now a third pump has the exact same problem. I believe that the shaft of the water pump is the part that seems to be failing / bending and it causes a leak from underneath the pulley.
Do anybody have a suggestion as to what could be causing the problem. Is my belt too tight? I find this had to believe since it is not really adjustable but has a tension pulley. Any suggestions before Friday when I have to change it again would be great. Thanks.