I am glad you were able to get it changed out. Sometimes the aluminum will "white rust" in the threads of the bolt and give you a hard time. But if you ever run into that again just put a drop of oil on the spot and warm it up with a hair dryer and then it will come out for you. Always put a dab of grease or anti seize on the screws that go into the body of the machine just to prevent it from ever happening again.
Billy