99 z71 water pump.... how bad to change?

I need to change the water pump on my father in law's "old" truck. Its leaking very badly, not from the front, but the back of the pump :scratches head: something I've never seen before. But anyway how bad is this to change?

Not hard at all. Search the forum for water pump & you'll find
details & tips. GOOD LUCK

Not that hard at all. But, I ran into trouble trying to unscrew the Fan Clutch from the pump, broke two $90 tools, and ended up cutting it off to save the pully and had to replace the clutch too. It apparently "cold fused" together.

The special wrench for the fan blade is huge waste of money,too thin.Here is another way,use an air hammer with a really long chiseling bit.Put the bit towards the end of the flat of the nut with pressure on it.It should come off.That is the way I do it.Keep the belt on when doing this

That nut is a bitch. I took off the entire assembly then put it in a vise and whacked my wrench with a 3 lb sledge 20 times before it came loose. The air chisel sounds interesting, I would think it may cut the nut. Maybe I just don't understand the concept. I know there are special tools for this job but I'm not sure they would work all the time.

Hmmm usually not that hard to loosen the clutch nut from the pulley hub. I've used a large adjustable wrench and a hammer. Usually comes loose with one or two good whacks. Again, keep the belt on and tight for this. When you do reinstall it, no need to tighten the hell out of it. Spin it on, use wrench and hammer to tap it tight. It won't come loose due to the engine spinning opposite the threading.

Double check that it isn't: A) the upper radiator hose leaking past the clamp, B) A loose or leaking water neck seal, C) Leaking water pump-to-block seals, or D) leaking/corroded heater core hose connector. Any one of those can look like the pump is leaking from the hidden/rear side.

Isn't the fan clutch a left hand thread?

I was thinking reverse thread also

FYI not a reverse thread. I figured it was but after about an hour of banging on it, turns out i was wrong, the only reason i realized it is because in the haynes manual the guy is holding the adjustable wrench in a way that would turn the nut counter-clockwise. they should really put a note in there about that. hope the info helps.