I had a similar problem with the lower rudder bearing on my 2001 Bav40.
essentially the design components are idiotic. An aluminium outer housing, inside which is a spheroid plastic bearing. Aluminium just loves seawater and the plastic used engorges sea water! What were they smoking during those long Bavarian winters??
I discovered the aluminium had totally corroded around the normally swivelling lower bearing putting pressure on the alreading expanding bearing and seizing it from any movement. The only solution we found was to ream out the hole in the bearing with an engine cylinder reamer by about 1-2mm, lavishly apply silicone grease and return the rudder.... now she turns with ease and I don't need shoulder muscles like Popeye! This is only a short term solution and will be repeated next haul out. The engineers here in Brisbane suggest the long term solution is cutting out the aluminium tube completely and replacing with a woven fibreglass shaft with cutlass bearing.
