Originally Posted by OldCoot
Sorry to disagree with you, but if the castellated nut is trying to turn, you have something else going on. The flat washer should shield the rotational motion from the nut. As I stated before, the cotter pin is to keep the nut from loosening. The cotter pin should fill the hole in the spindle. If it doesn't, someone used the wrong size.
You really are not disagreeing with me. (imo)
The flat washer rotates with the outer bearing from the pressure from turning the unit.
Rotating flat washer (some have flat areas to keep from rotating, mine do not) puts pressure on the castle nut, creating a forward or backward force.
This force is transferred to the carter key, the key is in place to stop the movement of the castle nut.
Why am I putting a larger key in the hole??? (caugh) Because the factory installed too small keys on the spindle aaannndd... (drum roll) there is movement and binding on the key and it (they) are bending. (one broke)
ie. the factory, installed cheap keys that will not hold under massive stress usages.
(I will take your advice and put (keep) the larger key on the spindle, that the factory should have done in the first place)