pull the safety pin out of the rudder pivot. I'd say go ahead and pull the pivot pin out remove the rudder and make sure everything is clean. When you replace the rudder make sure the spring goes into the slot in the center of the pivot pin. As you insert the pivot pin stop just before the 1/8" pins engage the holes in the rudder housing. Turn the pivot pin clockwise (I think) to increase tension on the spring then push the 1/8" pins into the holes. Try the rudder if it doesn't work increase spring tension more by backing out the pivot pin and turning further. Replace the safety pin when done.
Paddler's Truck Rack
Pull-Up Strap Handle Kit