Ask the Mechanic

The Wheels Are Turning

(Steve Thompson)

READER: I have always done my own wheel-bearing service on trailers and implements around the farm, and I have had pretty good luck not running them too long and ruining an axle. But, I have always wondered if there was any way of knowing when the bearings are tightened down right. Is there a special way to check the tightness of the nut?

STEVE: You are really ahead of the game on servicing wheel bearings on your equipment. I believe packing the grease in the bearing so there are no hollow areas that go unpacked is very important. I finally bought the tool that fully fills the bearing with grease.

Another thing that I learned the hard way in my younger years in the field was to always change the race (cup) that the bearing runs in if you change the bearing. This team has been many rounds together, and they do not like to be separated.

After the bearings and seal have been replaced, what I do is gradually tighten the locking nut while rotating the tire until it locks. Then, back the nut out about an eighth of a turn. There, you should be able to rotate the tire easily. What you are setting is called rolling torque.

I also like to change the locking device that secures the nut. There are many options here, from a cotter pin to a multipiece setup. Be sure and always use the factory locking device when changed.


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