I slid in a set of Mosers the other day into a spare axle. I left the thrush spacer in and both went in with the bearing edges flush with the tube flange. Now maybe I had a really worn spacer as there was about 160K on the axle.
Just in case someone is confused on the bearing orientation, The tapered bearings in the OEM (2 piece design) face out with the race thick section toward the tire. This means when the weight is on the bearing, the axle is pushed inward. The race is held in place by the drum backing plate and the bearing is pressed onto the axle shaft (before the hub is installed) and seats against a built in bearing stop on the axle which is the seal surface for the inner seal. So both axle shafts press in against a 2 inch or so section of round stock called a thrust block. IF the total distance of the right side outer race edge to the left side outer race edge is larger than the axle tube flange edge to edge, shims are used on the drivers side to achieve the correct endplay to allow bearing movement and heat expansion, etc.
The Mosers and Superior units have the bearing facing the other way so the weight on the bearing pushes it outward. Again, the backing plate holds it on the outside and a pressed on ring holds the bearing. The races thick section is toward the inside and what keeps it from going further into the tube is a spacer that is special to these one piece axle swaps. It is trimmed to allow the correct bearing orientation at the tubes end.
That said, AS LONG AS the thrust block isn't contacted by the ends of the two axle shafts, it should be fine. If the thought of the thrust black floating around loose on the cross shaft bothers you, remove it. Now if when installing the second shaft, you find that you can't insert the bearing fulling to achieve the specified measurement, YES, the thrust block will need to be remove. My view is to check first.
As a side note, I have another set of one piece axles that I bought second hand years ago. What I noticed is that the bearings are installed like the two piece axles (race toward backing plate) and have a huge press ring holding it on. Its more like a huge pressed on collar. and Im guessing it uses the thrust block as well. Anyone know of this brand?
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