Small Engines (Lawn Mowers, etc.): rusty hex nut, hex flange, flange nut

Question
 I am having trouble getting a rusty hex flange nut off a metal shaft so I can replace mower blades.  I have tried WD-40 repeatedly, but not luck.  The manual says when putting it on to torque it to 100 foot-pounds.  Would getting a torque wrench help get it off?


Answer
 Hello Allen:

 Try PB Rust Catalyst. Allow it to Soak for 4 to 5 hrs and Keep Spraying every Hour or So. Take a Hammer and a Flat Punch and Hit the Nut on the Flats. A Breaker Bar or Long 1/2 Torque Wrench Should Work if the Nut is Going to be Remove without an Impact Wrench or Heat. If you have Access to Compressed Air, then an Impact should Remove the Nut with Little Effort After the PB has Worked on the Rust. If this Doesn't Work, then Use Heat on the Nut and Once the Nut is Hot, Remove the Nut. BE CAREFUL HOT !!! Hope this Helps. I am here if you Require more Assistance. Let me know what Happens, Please. Thanks.

 Good Luck

 Respectfully

 John