Gas:
I had this in my folder also. Its for a national seal.
National 471787
When you take these apart look them over close. Im sure you will
. But what I have seen a few times in my limited experience.
If the bearings were not kept adjusted correctly it can hammer on the Spindles Bearing shoulder.
Check to be sure someone didnt prick punch, stake a loose race in place.
Take the washer off and make sure the nut can go up to bearing. Making sure your not adjusting bearings with interference from the threads.
Watch the seal surface not being dinged from rough assembly.
take care
Luke