3,500 pound Dexter axle bearing pre-load?
I'm putting a new drum-brake system on a single-axle cargo trailer. It has a torsion suspension. I have the components ready to go and one of the old, non-brake assemblies removed. It occurred to me, ...
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Ron3rd wrote:The bearings are NOT supposed to be preloaded.Lynnmor wrote:Ron3rd wrote:Ranger Smith wrote:
From what I remember when doing mine it was torque axle nuts to 50 ft. lbs and then back nut off to next cotter pin slot.It is a little more involved than "hand snug" as everyones idea of hand snug is different
That is correct, and I don't remember the exact torque required but it's in the Dexter instructions available for download. Basically, you torque the bearing to the spec and rotate the wheel to seat the bearing and then back off to the first cotter pin hole. My old trailer had Dexter 3500 lb axles and I did this several times, easy process.
BTW, most techs I've watched don't use a torque wrench; they tighten the nut down with a large Crescent wrench or Channel Locks, rotate the wheel and then back off the nut. Probably close enough but I prefer to go by the book as it's no harder.
Wrong again, this will result in a pre-load condition.
Wrong? Then Dexter's instructions are wrong. Take it up with the factory! The bearings are supposed to be preloaded btw.
They are to have a small amount of play commonly called end play... There is often a spec for this, but it is so small as to need a dial indicator to measure it.Most people don't have one (I do) so the procedure of torquing them while rotating the wheel, then backing off the nut then hand tight, then backing that off was developed so most junior mechanics could get it close enough.
The reason for the endplay is to allow for expansion when the parts heat up. When they are at operating temp, the end play is close to zero.
If you have no endplay when it is cold, then it will be tight when hot, and the bearings WILL fail.
Go back and read the manual again. Slower this time, as you didn't comprehend it all the first time.
