The controls on this site will not let me add to my original thread. It is too old, just like me. So, here is a link to the thread and my reply...
I am the OP. Stuff got in the way and I never did replace the bad tie rod end dust boot until this weekend when I noticed that the right boot was completely missing.
Since I will be leaving soon on a trip, I wanted to find a boot locally. Napa universal boot 650-1178 would fit the shaft but it is too long. So, I trimmed off ~7/16Ē. I should have trimmed of at least another 1/8Ē.
That brings me back to the castle nut and what initial torque should I use? The Workhorse spec of 300 ft-lbs seems excessive.
I decided to measure the break away torque, but first made some witness marks on the nut and mating surface. I applied CCW torque in 25 ft-lb increments up to 100 ft-lbs. The castle nut did not move. My next torque wrench capable of measuring torque in the CCW direction started at 200 ft-lbs. The castle nut broke free well under 200 ft-lbs. Great! So, either the spec is wrong or the factory did not read the spec.
In the CW direction I could measure the torque in small steps. At 75 ft-lbs a slot in the castle nut lined up with a hole in the tie rod shaft, but the witness marks did not line up. At 125 ft-lbs the next castle nut slot lined up with the tie rod shaft hole and the witness marks were lined up.
So, there we have it. Based on a sample of one. Tighten the castle nut to 75 ft-lbs. Then tighten the castle nut further until the next slot is aligned with the cotter key hole. The resulting torque will be between 75 and 125 ft-lbs.
I hope that helps the next guy.