How do you remove fan clutch from the water pump on a Chevy astro van 1998?

One way is to get a lerge crescent wrench and adjust it around that big nut behind the fan and then after you get whatever is in the way out of it, you take a big hammer and give it the what for to take it off counter-clockwise. I mean a real wack like you're hitting it over the fence. It's all in the head speed. Then once it breaks free, just spin it off with your hand and when you reinstall it just give it a little wack after it's snug. You could also try a air-hammer chisel on the flat of the nut in the direction you want to turn it off(left-hand thread). I almost forgot, DO THIS ALL WITH THE BELT ON OR IT WONT WORK. Good luck., PS, the right tool is a special spanner wrench that fits into the little holes on the pulley to hold it while you use a wrench to turn it off. I like the first way better.