Tapered wheel bearings

[bobhustead]

I put wheel bearings in my boat trailer last week and, for some reason, read the instructions. Said to tighten out the slack and LOOSEN to the next slot in the castleated nut that will allow insertion of the pin. I have for 60 years believed in a preload, so I go to "no slack" and tighten to the next slot in the nut. Have I been doing this wrong?
Bob

 

[DrEntropy]

How many bearing failures have you had from "overtightening" that nut? I'll bet not one! I'll only back off the nut if after getting the tension to a "no slack" point and the slot is closer to the pin hole by backing it out than winding it in... but it's likely no big difference.

 

[BobHaskell]

Our '80 MGB has the same front axle tapered bearing setup as the later Austin-Healey 3000s.Same arrangement as all but the earliest Healeys, just different parts. The Healey manual states that you should adjust the shims between the the outer bearing and the bearing spacer for no end float when the nut is torqued to 40 to 70 ft-lb. The MGB workshop manual states the end float should be 0.002" to 0.004" when torqued (same range).

There seems to be some latitude.

 

[DavidApp]

The boat trailer like the TR3A bearings do not have a spacer between the inner race so you can tighten the race to the point it will not turn. If the MG is the same as the MG Midget I have been working on there is a spacer and shims between the bearings so you are clamping the bearing inner race against the spacer. The shims allow you to get a precise clearance. I checked the end float with a Dial indicator and changed the shims to get the desired 0.002" to 0.004" float.

David

 

[LarryK]

I tighten all my trailers to 20ft/lbs, check, retighten to 20ft/lbs, then back o slot. Never had a failure in 50 yrs. Tires are a different story.