[Will N]

The procedure for adjusting the bearing is to tighten the crap out of the nut while spinning the wheel. Then back off the nut and re-tighten only to the point where you can line up the cotter pin. If you are doing this and you still have play something is wrong. Do you have original hubs? The original hubs only had dimples that the bearing races seat against. I've heard that these dimples don't provide a positive stop for the races, and it's possible that as you tighten the nut, you could be forcing the races further into the hub. You'd never get the right preload. Repro hubs have a seat machined all the way around for the race to seat against. A much better design!