My trusty old craftsman floor jack handle would not turn the release gears. Upon close inspection it turned out that the end of the hanldle that is inside the jack is hex shaped and turns a bolt head that turns the gears. The handle end had rounded out and would not turn the bolt any more. In order to repair it I drilled out the end to almost the outside diameter of a 1/4 dr 1/2 inch socket than used my shop press to press the socket into the end of the jack handle. Problem resolved.

 

Cool.. great tip, Cuz I been kludging mine along for years.