How do you break loose the fan and shaft from a '98 Chevy three-quarter truck water pump?
If you can't get the fan clutch off: get to the point where you have all of your hoses off take off the water pump on my 98 it's 14mm on the left facing the mtr. And then 15mm on the right side remove the pump. Open the inspection plate on the back of the water pump and jam the water wheel portion of the pump with a C-Clamp carefully. My pump I believe is ok, I'll see I believe it was the seal that gave. The truck is like brand new 30,000 original miles govt. owned. Then I took a one-inch and a half standard wrench because I didn't have metric that big and turned the nut the same direction as was on the arrow of the fan blade. Most likely plastic blades but be careful you can easily take out that wonderful GM radiator it's so paper thin I left mine in and kept my hoses up so not to loose fluid out of the radiator.