Re: Trailer Bearing rebuild
I pulled one of the hubs off and the outer bearings looked and felt good. When I put the nut back on and finger tightened it, it would work itself loose and the hub would become loose. I tightened the nuts down a little tighter then finger strength. The cotter pin does not sit snug against the nut. Is this somewhat normal or should I replace?
When you put in a new bearing, or even a repacked old one, the grease sometimes takes up a little space. So you have to rotate the hub forward and back while tightening the nut
by hand to work it into position.
Secondly, sometimes the rear/inner seal can put up a lot of hydraulic resistance if there is an air bubble while sliding the hub back together. Once that "burps" and everything goes together well you check it by adjusting it to working endplay, and by rotation of the hub by hand you can assure it is properly installed. Usually I bolt on the wheel so I can get it spinning easily to get the bearing seated fully and notice if I need to readjust again. After a while you get a feel for it.
Last, do not "preload" your bearings. Most manuals that cover bearing packing will list a specification for end play of so many thousandths. If you tighten a bearing down to "preload" it you are reducing or eliminating the grease cushion which bearings are supposed to ride on- bearings wear out from metal-to-metal contact and/or contaminants in the grease. Forcing bearings into their races only cuts into their lifespan; rollers are not supposed to ride on the races- they are supposed to be suspended just off the race by the thickness of a molecule or two of grease. Too much pressure, grease is forced aside, and early failure is imminent.
As far as working the nut back on, as a general rule when the nut has been turned in to contact point (tight) by hand, rotate the wheel once. Then if it has stayed tight, back it off the least amount needed to slip the cotter pin in to the axle hole. Usually there are two holes in the axle roughly 90 degrees separated so that cotter pin can be installed without loosening the nut too much. One hole will line up while the other might still be partially inaccessible behind the nut.
The cotter pin will not usually be tight to the nut- it is merely there to keep the nut from backing off. The slotted washer only provides a rotational buffer.
It sounds like what you are describing is the bearings, seal, and hub settling together when the nut "loosens up" and as previous poster described there needs to be a keyed washer in there as well.
This seems to be a nice tutorial
And page 23
of this manual has a nice schematic of the parts
Too loose is just as bad as too tight. Do it right!
Hope this helps
