As far as the rebuild kit goes, my mechanic (the guy I had check out the car before I bought it because I'm unfamiliar w/ merc) said that the leaky part of the p/s pump was a "pitman arm seal" and that in his experience it means that a rebuild will just end up being another pump. Is this guy lying to me just to get me to have him do the job?

Also, if I do take the pump off, is tension automatically put on the belt or do I need to add tension myself?

Thanks for your help thus far.