With some square neoprene seal ring material, some super glue, and an X-Acto knife, you can change that seal without having to do anything other than unscrew the gland nut. Wrap the O ring material tightly around the torque tube, make a cut in the seal material at a 45 degree angle, and glue it together. If you put the cut at the top of the tube, it doesn't even have to be a very good joint!
Jerry