Canadian Man,
Well, after much creative thinking, I think I can answer your question on how you can fix your broken rotating return unit.
Visit my newly posted R&O page for broken rotating return units which are no longer on warranty and using the DIY parts listed you should be able to get it up and running again by looking here...
http://pages.infinit.net/lambertv/pa...rn_R_and_O.htm
and for those interested in a brief pictorial history of rotating return units see here...
http://pages.infinit.net/lambertv/pa...s_SeaSwirl.htm
Van