How do you all set your trailer bearing preload....?

I noticed the hubs on the front axle of my gooseneck stock trailer were running slightly warm. (as in when I put my hand on them they felt wam while the hubs on the rear axle were cool to tyhe touch after 70 miles of towing..)


So I ought a new set of bearings for the whole trailer, pulled one of the offending hubs off and found it to have plenty of nice clean looking grease and could see no bearing wear, rollers all looked good, races looked good, very little side to side play in the cage.. so feeling really confused I decided to replace and repack the bearings in that hub and see what happened....... Took it for another 70 mile tow and found that the hub with the new bearings was ice cold to the touch, same as the rear axle while the hub that I have yet to replace the bearings in was slightly warm. Since I just bought the trailer ( the rear axle that initially had the two cool hubs is new) I'm thinking the previous owner either had the preload set too tight or too loose when the replaced the rear axle and probably repacked the front axle. To be honest I didn't really take notice of how tight the castlenut was when I removed the hub. I always tightten the nut while spinning the hub until it is snugish with a crescent wrench and then back it off to the next position for the cotter pin.

How much preload does everyone else put on their trailer bearings???

Just curious.

Think I'll replace the bearings in the other front hub tonight anyways.

 

I tighten the nut down usually with a large pair of channel locks if I don't have the right size wrench handy. I tighten it down by feel. I get it snugged up, then I back it off and tighten it hand tight.

That leaves it snug enought to not have play, and not too tight to be in a bind. Thats all you really want.

 

You're on the right track.

I tighten by hand to zero play - sometimes a wrench helps - and back off to the the first available slot in the castle nut. If I can feel play, it's too loose. If it won't rotate adjusted as easily as it would "loose" - it's too tight. I like to seat the bearings first with about 20 ft-lbs of torque.

 

I always go by Champion Trailer's article.

Basically, you want to leave a little room for thermal expansion; prevents binding.

 

if u can put your hand on the hub after a 70 mile pull you have nothing to worry about, i use a raytek heat sensing thingy & get 150 to 200 degrees on my loaded trailer... unloaded it's cooler by 75 degrees. but it all depends on how fast you go.......

 

Assuming you have Dexter axles, you can go to their web site and they give detailed instructions there. For mine, clean and repack, tighten to 50 ft-lbs while spinning the wheel, stop wheel and back off the nut and then finger tighten to the nearest slot on the castellated nut.

 

What MX429 said is the way I do it too, except after the initial tightening, I spin the wheel a few times to 'seat' the bearings, THEN back off the nut and hand tighten.

If you're getting one axle warmer than the other, I'd be thinking that there's more load on the warmer axle, the bearings are tighter or the brakes are adjusted tighter on that axle.

As long as they're not so hot that you can't touch them I wouldn't be concerned.

chaikwa.

 

70 miles at 70 MPH............

Actually the trailer is running uphill more than I'd like it too........ So there is more load on the rear axle.

I found that the preload was set too high on that front axle for my taste. took a bit of effort to back the castlenut off with a crescent wrench. So I went ahead and changed the bearings in that hub, repacked etc and took another test drive. Now after another 70 MPH run all the hubs are cool to the touch.

 

Are you running brakes on one of the axles? They will generate alot of heat.

 

... especially when they're dragging

 

Nope it wasn't a brake problem. Like I allready mentioned the heat was caused by the previous owner setting the preload too high. Replaced and repacked bearings, set proper preload and voila! Axle runs cool like it's tandem counterpart.

Now if I can get my alignment issue sorted out. O:X

 

A lot of worry about nothing. My bearings run warm to cool, usually the rear axles run cooler. Best not to have play in the bearing, a little preload is ok. Be sure to check the preload after a few hours running. They will wear in and reseat on a new bearing.

On a stop, get in the habit of feeling the hub for heat and hitting the tire at the top on the outside. Any loosness will be apparant. I am running over 7500 pounds per axle on the same bearings that you have with 5000 pound axles.

 

Thanks H.I.D That's good advice. And someth9ing I have always done (I drove OTR for a time)

Your axles use 25580 and LM67048 Bearings? This is one thing I asked the axle builders a few days ago... If the spindle is the same what is the difference in the makeup of the axle?? The only difference I can see would be tube size.......

I am positive the preload was set to high because on a COLD axle it took EFFORT to crack the castlenut loose! Plus the shim washer was scored up and bent!

After I changed the bearings and races, repacked and set the preload properly, the axle runs cool and free and I'm happy.

 

'the wheel is quite different and uses a larger race on the inner bearing, but the bearings are the same. How I found that out was using a supplied bearing on my 7100 pound axles that was marked for 5000 pound axles on the packaging. I did not dare to use them until checking and that is the difference.

I am sure that the axle tube is lighter as well as the suspension,.