Small Engines (Lawn Mowers, etc.): belt change, engine crankshaft, vice grips

Question
Hello Michael,

I have an older Toro 8HP riding mower.  It needs a transmission belt.  The directions say that I have to remove the deck clutch from the lower half of the engine crankshaft.  One nut holds everything on the crankshaft, and of course when I turn it, the upper part of the shaft moves, turning the pulley with the transmission belt.  How can I get this nut off without turning the shaft?  I can't get a pipe wrench around the crankshaft, and I tried putting vice-grips on the pulley, but I am afraid it will bend it if it hasn't done so already.  Thanks in advance.  

             Regards,

               Jo

Answer
Hi Jo,

The best way to loosen something like that is to use an impact wrench.  Its' hammering effect allows removal of fasteners without putting torque on the rest of the assembly.  These are available for rent.  Other that that, I don't know how you can keep the pulley from turning.  You are right, damage might occur if the pulley is held with vice grips or a conventional wrench.  Also available is a strap wrench.  It is adjustable and made to wrap around round objects like pipe.  

Let me know how you make out.
Michael