1999 Chevy Suburban

I had the same experience the first time I had to replace the water pump. You need to get a good strap wrench and secure it around the fan belt 'shroud'. Wedge it agains one of the brackets because you're going to need both hands and lots of time to do the rest. Once the strap wrench is secure, get a large crescent wrench and adjust it to securely fit the clutch nut. Now, stand on the passenger side of the truck, grasp the wrench and pull like heck. Mine took me almost 3 hours to break loose. I ended up running a length of 1/2" rope through the hole in the end of the crescent wrench so I could brace myself and really put some oomph into it. The 2nd pump was a lot easier.