I am replacing the small plastic end of the manual tilt cable. While at it, I'm wondering if I should/can be doing any other maintenance. While I have been rinsing well and applying WD40 after each trip, it has been getting stiffer to operate. Is it possible to (and should I) change the fluid? Is it possible to get the knurled knob off? Earlier post looked to be cut off right when they got to the good part. <br /><br />Many thanks