Thanks for all the tips guys. I'm going to try some of the suggestions next weekend. If still no luck, I'll have to buy new ones. If I get lucky, I'll let you all know what worked.

If you have time before the weekend you might try heating the housings, giving them a quick blow with a hammer, and them soaking them with your favorite penetrating oil and letting them cool--repeat several times. This seems to help draw the oil deeper into the threads.

Good Luck