If they are frozen on that bad it might be necessary to take the mower to a garage with an impact wrench. If the bolts have not been extracted for a long period of time, this is usually the only way to get them to break free. Before puting them back on make sure you use antiseize compound (available at any Auto Zone or Advance) on the threads. It will make it a snap to change or sharpen blades in the future. Make sure you use a 6 point socket and not a 12 point. 12 point socket will round off the bolt head long before they break free.
Scott Deaver B&S Authorized Master Service Technician, June 2005
