The rudder on my D2b has become very stiff on its hinges during this season.. I disconnected the cables at the rudder horn, and it's clear the problem is in the rudder not elsewhere in the control circuit. Removed mylar seals without effect. No visible damage to the rudder, and no foreign objects visible between rudder and fin. Before I remove the rudder, has anyone out there encountered a similar problem? Glider has 650hrs TT, always hangared.

Thanks in advance for all suggestions!
Ian IN