Stuck parts.
I have had some luck loosening stuck parts by using penetrating oil. WD-40 is great stuff (I think it will team up with duct tape to save the world someday). WD-40, however, isn't a great penetrating lubricant. Try using PB Blaster or something specifically formulated for the purpose of un-sticking frozen parts.
Just my 2 cents,
Dave
[URL unfurl="true"]http://www.pbblaster.com/[/URL]
