My fan clutch is wobbly and my water pump is leaking - it leaks out as the engine cools. Autozone offers a tool for loan, but with the tool, two of us (one above the pump and one below) were not able to develop enough torque on the brass nut to break it loose. I find this design a bit odd, as you have to reuse the belt pulley and the fan is captured on the inside of the fan clutch rather than being mounted on the outside. So, working around the fan and clutch, I removed the eight bolts and pump. I busted the plastic impeller off of the pump, removed a brass sleeve, a steel retainer, spring, and rubber seal to get at the shaft. See photo. Now I have the pump shaft clamped in the vise and I am torquing with my largest crescent wrench, applying about 10X the torque we were able to bring to bear under the hood, but it will not break loose. Next, I will grind some flats in the shaft to see if I can get a better grip with the vise. All other ideas are welcome. I could put a pipe over the loaner tool, but I am certain I would destroy it.