Wheel Bearings

Ted in NE-OH

Well-known Member
I need to repack the wheel bearings on my tractor hauling trailed.After repacking the bearings and tightening up the axle nut ho far do you back off the nut before you put the cotter-pin in. One notch, 1/4 turn. 1/2 turn or what??
 
The bearings need to be somewhat "tight" or preloaded in order to work properly. Too loose and they will run out of true and wear prematurely, to tight and they will simply run hot and wear out prematurely.

That said, tighten the nut with your fingers until you feel it get as tight as you can get it. Then use a wrench and go just a little further. What your looking for is when you spin the tire by hand you want to feel just a little bit of drag on it from the bearings being preloaded. From there you can either go just a little further, or a little back to make the pin hole line up with the slot in the castle nut. Basically you don"t want to go another half round tighter to line up if you can go 1/8 round back (and not get loose) to line up. In the end the main thing is you want to feel that little bit of drag on the wheel when spun by hand to know the bearing have just a little preload and aren"t loose.
 
I tighten the nut as tight as possible, with a large pair of channel-locks. This is to pull everything tight/seated and then I back off to closest slot or the next one.
Spin the wheel and recheck.
 

I always tighten the nut until the wheel will not turn, and then back it off just to the point where the wheel DOES turn freely, then tighten it just enough so one of the slots lines up with the hole.
 
To do it CORRECTLY, it should be set with a torque wrench. If a torque wrench is NOT available, tighten the bearing pretty tight with a wrench. Then spin the wheel a round or two and stop the wheel. WITHOUT MOVING THE WHEEL, loosen the nut with the wrench until the nut is less than finger tight. Tighten the nut with your fingers as much as you can and put in the cotter key. Simple as that.
 
CONTRARY to what some "experts" say, wheel bearings are NOT to be "pre-loaded".

What ever procedure you you use to set them, the end result should be .001" to .oo5" of ENDPLAY.

Don"t believe me? GOOGLE "Recommended Practice RP 618", which is the industry standard practice for setting wheel bearings.
 
I do it similar - I tighten until the wheel turns with difficulty (or not at all) to set the bearings and races then back the nut off until it is completely loose and turn the nut to one of the slots with my fingers. No wrench in the final adjustment. I give it a spin and it should do so easily. I also check the hubs to make sure it is running without heat the first couple of times I use the impliment or trailer.

I've seen a lot more bearings lost due to over tightening at service than because of being run dry.
 
It would be interesting to know how many failures result using some of these instructions. Imo,tightening to the point of causeing resistance in wheel turning damages the bearing regardless how it is adjusted afterwards.
 
(quoted from post at 17:29:49 08/07/14) It would be interesting to know how many failures result using some of these instructions. Imo,tightening to the point of causeing resistance in wheel turning damages the bearing regardless how it is adjusted afterwards.

If bearings were that fragile, they would be useless. All bearings require clearance depending on application and in this instance, clearance must be determined.
 
(quoted from post at 09:29:49 08/07/14) It would be interesting to know how many failures result using some of these instructions. Imo,tightening to the point of causeing resistance in wheel turning damages the bearing regardless how it is adjusted afterwards.

Really?? I have replaced the front brakes on countless cars and pickup trucks. Every single one of those jobs included repacking the front wheel bearings. NEVER did any of those wheel bearings fail.
 
Here's the info, direct from the Timken site.

Since it's geared to heavier stuff, the 200 ft lbs in Step @ is gonna be too high for SMALL spindles, but the rest, including the .001" to .005" of endplay should hold true, IMHO.

<img src = "http://i167.photobucket.com/albums/u125/27Grainfield/Stuff/tapered_zpsc3b699cb.jpg">
 
Regardless of your procedure, you will find on most applications using a hole and cotter key that one hole is too loose and next one is too tight for ideal settings. Chrysler always used a little locking nut over the adjusting nut and you could select several different settings for the cotter key. I always liked that but am sure that some don't.
Another thing, keep that wheel turning while adjusting. Those rollers have to work their way up into the inner race as you turn the wheel. I saw this magnified in the adjustment of the transmission bearing on the magnum tractors when in service training at Racine. Checking for end play, turning at least ten times while tightening down the end cap. Then check end play. You get one shot and then you have to turn shaft several times again for next measurement. You might measure .002 end play on first try and then get absolutely no reading on the next try until you turn the shaft again.
 
Read the instructions from Timken posted below. I guarantee if you put 200 FT pounds of torque on the nut the bearing is going to load up and wheel will encounter significant resistance (mostly stop completely).
 
10 people are probly going to give you 10 different answeres on this. I not only pack the bearings with grease, but also the bigger part of the hub. Install with wheel mounted on hub, and tighten the nut with wheel rotating. No need to tighten any further than the wheel dragging pretty good. (obviously you pressed the races all the way in if you replaced those). Then loosen the nut back to somewhere around finger tight. Wheel should turn freely (normal) at this point. Check end play by moving top of wheel in and out. If no end play losen nut. If end play then tighten it. You will find that point where you are right on the line of having or not having any play. I ussually either tighten or loosen to the closest hole for cotter pin at this point. I like to tighten a hair to get to that hole if I can, or loosen if I can still end up right on that line of no end play. You should still be somewhere in the finger turning tightness at this stage.
 
I pack the hub as full as I can with grease. Spin the hub while tightening the nut. When you start to either feel resistance on the nut or the hub turning, back the nut off to the closest hole and install the cotter pin. I have rebuilt gearboxes and choppers that have pre-load on the bearings and they turn a lot faster than a wheel hub on a tractor, truck, or car. As long as you don't go stupid tight a little tension on the nut won't hurt either. With disk brakes I leave the nut slightly snug so it won't drag when turning.
 
Timken did make a change to a preloaded bearing setting for trailers hauled on rail cars. It was found that those trailers would have early bearing failures due to movement of the rollers while being hauled. Since the wheels were not rolling the bearings would get grooves worn in them.

Another thing that sometimes is misunderstood is that the inner bearing races in the cone part of the bearing is a slip fit on the axle to allow the race to slowly turn on the axle to ensure the race wears evenly.
 
ooh, really? they are a roller brg. and require a small amount of preload to seat them then back off till zero preload and closest to zero endplay as possible then lock nut with cotter pin in the closest hole available. this is done while turning the wheel.
 
(quoted from post at 21:39:54 08/06/14) CONTRARY to what some "experts" say, wheel bearings are NOT to be "pre-loaded".

What ever procedure you you use to set them, the end result should be .001" to .oo5" of ENDPLAY.

Don"t believe me? GOOGLE "Recommended Practice RP 618", which is the industry standard practice for setting wheel bearings.

working with old, used parts, never new if I can help it, I'm with Bob here.
Tightening a very old bearing down until the wheel won't move will
probably make it junk.
I snug them down with a wrench carefully to 'seat' everything, turning the wheel the entire time.
'Snug' being very light. pushing the outer washer in with both thumbs usually seats everything, the initial wrench is just to squeeze the grease out between parts.
Then back it off and do it again with my fingers only.
When I think I have it perfect with turning and pushing/pulling,
if the hole lines up, good....done.
If it doesn't, I loosen until it does. I never tighten to get it aligned.
I treat them just like valves. a thousandth too loose is better than too tight.
 
FSM for my 90 Dodge says to spin the wheel while tightening the bearing nut to 35 ft-lb, stop wheel, back nut off, and finger-tighten.

That Timken info seems to be for large tractor-trailers, not pick-ups and goosenecks.
 

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