I'm repacking the wheel bearings on my car trailer. Instead of the castle retainer that my cars have always had, it uses castle nuts, which give me a "too tight" option and a "too loose" option for preload. I know that different vehicles have different specs for tapered wheel bearing preload, and I am wondering what the proper procedure is for the trailer.
Loose
Too tight is not good.
Is the logic that when things heat up under load, it expands, so you want to have some slack in the system?
For brandy new bearings, don't they say tighten to XXX ft.lbs. then back off 1/8 or 1/4 turn?
The only application when loose is good.
"Generally, a setting ranging from near zero to slight preload maximizes bearing life. Some applications use moderate preload to increase rigidity of highly stressed parts that would otherwise be adversely affected by excessive deflection and misalignment. Excessive preload, though, can drastically reduce bearing fatigue life or cause high temperatures that can quickly lead to bearing damage."
Personally I feel the best solution on tapered roller bearing pairs is to have a spacer sleeve between the bearing that is precisely the right length (or slightly shorter and some shims to make up the difference) for a small amount of preload and having the adjusting nut torqued to clamp the whole assembly together, producing a very stiff spindle assembly. This takes a little bit of trial and error in the setup phase.
Unfortunately most of the trailer spindles I've seen only have on cotter pin hole so for those I'd err on slightly too tight.
Also keep in mind that increasing end play simultaneously increases radial play.
Use a castle retainer and a regular height nut to come close than a castle nut?
MGB's and C's used a spacer and shims to set like ,002 clearance bearing dry, paxk it, and torque that hombre to like 100 ft-lbs
I have adjusted the nuts with a belt sander to fine tune the setup of this kind of thing. Just don’t take to much off at a time.
Snug up tight and back off until the holes line up.
Good info. Thanks.
If the nut falls in between I always choose loose with trailer bearings.
glueguy said:If the nut falls in between I always choose loose with trailer bearings.
That's what I did.
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