Sven,
Research this issue please. We had play in the rudder of VOR and when we did the haul out in June, one of our projects was to fix the rudder post. Besides replacing the packing gland, including the brass fittings at the top of the tube, we had to create a new bearing. Greasing the tube was discouraged, since the interaction between the grease and ocean water creates a messy emulsion that you really don't want.
Instead, we were advised to use a designated mix of west epoxy and graphite. We predrilled holes into the rudder post tube and injected the mixture using a syringe, with the rudder held in place. It was freaky after it hardened because we couldn't really turn the rudder. It took some effort to break it free, but now it is just about perfect -- good as new, or even better than new. It moves smoothly and there is no wobble or 'thump' in the rudder when we are hit from behind by a swell or wave.
Jim McCone
Voice of Reason, E-32-2 Hull #134
Redondo Beach, CA