I just replaced my rollers. I have an Andersen Perma Shield. Like the
other poster said, I have a wood strip on top held in with about 5-6
screws.
What I did is lock the door closed, then I lowered the wheels with the
adjusting screws. Then I removed the strip of wood on top ( with the
door locked closed, it should not fall in towards you). Then open the
door carefully and it should come out from the inside. But be prepared,
the door is heavy.