Ya that fan clutch can be PIA to get off.
A few tips.
The nut is regular (right hand) thread.
reversed (left hand) thread.
36mm wrench or large crescent wrench.
Use plenty of penetrating oil.
You can keep the belt on to help hold the water pump pulley down.
You can crank down on the belt tensioner bolt to help hold the pulley some more.
There is a tool you can buy to hold the pulley down with called a spanner wrench. http://www.napaonline.com/Catalog/Ca...157_0009852042
Here is a list of suggestions from other members. This will be posted in the FAQ.
Use a strap wrench to hold the pulley. http://www.sears.com/shc/s/p_10153_1...=Y&origin=prod
Use an air chisel to hit the nut on the corner. I could see it damaging it but if it is a last resort.
Put 2 bolts in 2 of the holes in the pulley and wedged a large flat head screwdriver between them to hold the pulley.
Put a large adjustable wrench on it and hit it with a hammer.
Or build your own spanner wrench
Or use a
Lisle LI43300 Pneumatic Fan Clutch Wrench
You won't need to hold anything and it will come right off. Once you use this tool, you'll wonder how you ever got by without it.