Re-packing the bearings

[Dan Simon]

I just picked up the Boler after having Les Schwab throw on two new trailer tires and repacking the bearings. I bought the trailer two years ago and was remiss in not repacking them.

The tech told me the nut holding the bearings to the axle was only finger tight and in essence the only thing holding my wheel on to the axle was the cotter pin !

All told ($175 is all) I have two brand new tires and greased up bearings and peace of mind.

I'm off Thursday night to check out the new Washington State Forest Service park called Middle Fork Campground. It's just outside North Bend. I'll report back with pics.


Dan

[Loren G. Hedahl]

That"s what cotter pins are for.

[Kurt in BC]

some wheel bearings only call for the nut to be finger tight and then the cotter pin slid through. You may want to check with someone one here for sure as overtightening the bearings can cause them to go from too much pressure.

Anyone know the torque specs of the Boler hubs?

[Brian B-P]

My Boler has Dexter hubs. I found the complete bearing adjustment processes described on page 50 of the Dexter technical manual, which is available from their web site, which is in the Helpful-Links. The end result is that the nut is to be finger tight during operation. With not much more than a year since an RV shop rebuilt my axle, and less than 10,000 km of use, I have not yet disassembled the bearings, so I don't know how tight the bearing nuts are on my axle.

[KevinDR]

Well, A wheel bearing is a wheel bearing is a wheel bearing, be it on a trailer or any vehicle. That is how a very experienced mechanic described it to me. He taught me how to repack and re-install wheel bearings.

I was taught the following, and it has never failed me yet.

The bearings are indeed a simply a nut with a cotter pin preventing it from rotating. You tighten the nut until really snug. Spin the wheel a good number of times so that the new grease sets in and is not contributing to the play or the tightness. You may even end up having to tighten it more after you spin the tire.

Then what you do is loosen the nut one eighth of a turn (one slot for the cotter pin). And you check for bearing play by wiggling the wheel. Sometimes you can even put the tire back on to get more leverage and feel the teeniest of wiggle.

The mechanic taught me that you should have barely a perceptible wiggle....the teeniest amount. If you are not sure, tighten it back up. If you get no play in the wheel, it is too tight. Then back it off one "slot" again. The key is not to run the wheel where the bearing is constantly grinding. The key is not to run the wheel with a lot of wobble. The key is to rotate the nut so that the cotter pin goes through and you get the teeniest play or wobble.

I am sure others on this forum can extrapolate or correct it.

I was taught that the best is the science of "feel" on the wheel and you want to get only the tiniest amount.

Kevin.

[DAVID K]

Finger tight is close. The rule of thumb is to torque till tight than back off the nut one or two flats so that you can move the backup washer with a screwdriver than slide in the cotter pin .

[Bill Abbay]

Dan,

Not to pile on, but having repacked many dozens of bearings, I have to agree with every reply you've gotten. Finger tight is what it's supposed to be, and you can't go wrong using Kevin's procedure.

Now, if the mechanic seemed to think "finger tight" was not enough, I'm worried about what he thinks is correct and how much he tightened yours. Practically every reference I've read on premature bearing failure lists overtightening as a major cause.

[Con]

My brother who was a heavy duty, automotive and aircraft mechanic all his life taught me pretty much the same way Kevin has described.

[Dan Simon]

Allrighty then.

I'll call Les himself first thing tomorrow am and ask what their policy is and my concerns. I can swing by as I leave tomorrow for Middle Fork. It will be my first "in field
test of my McCulloch generator.....works great at home.

Dan

[Pete Dumbleton]

Here's a quote from the Dexter PDF on bearings -- It is my experience that various wheel bearings require different "preload" (initial tightening while turning the hub) torques in order to properly seat the various components -- Indeed, there should be a certain small amout of play in a cold wheel when one is done, perhaps to allow for expansion at running temps.

1. After placing the hub, bearings, washers, and spindle nut
back on the axle spindle in reverse order as detailed in the
previous section on hub removal, rotate the hub assembly
slowly while tightening the spindle nut to approximately 50
lbs.-ft. (12" wrench or pliers with full hand force.)
2. Then loosen the spindle nut to remove the torque. Do not
rotate the hub.
3. Finger tighten the spindle nut until just snug.
4. Back the spindle nut out slightly until the first castellation
lines up with the cotter key hole and insert the cotter pin.
5. Bend over the cotter pin legs to secure the nut.
6. Nut should be free to move with only restraint being the
cotter pin.

The procedure is slightly different for EZLube hubs because they use a different fastener than a cotter pin.

[Loren G. Hedahl]

That's the same procedure I was taught by my dad (a machinist) as a kid and is the same as any auto repair manuals that I've read for front wheel bearings on a rear wheel drive auto.

I was told the initial 50 ft lb torque is enough to ensure the races are seated down completely in the hub, but not so much as to damage the polished surfaces of the bearing.

The one flat back off is to provide metal-to-metal clearance. You really don't want the metal of the rollers to contact the metal of the races! When it does, wear results.

You want the rollers to run on a thin layer of grease. The result is no wear.

The objective is to keep a layer of grease between the rollers and races at all times. Old technology used asbestos fibers in the grease to make it stringy. The fibers pulled the grease around the little rollers and did a good job of this.

Now that asbestos has gotten a bad name for itself and better lubrication technology provides exists, even better results are normal. When was the last time you ever had a wheel bearing failure?

My opinion is with absolute cleanliness (no grit), a modern lubricant of the recommended type and the procedure in Pete's post, a new quality made wheel bearing would last the lifespan of several FGRV's.

Practically, I hedge my opinion a little. Before I leave I always grab each wheel on the sides and shake to be sure everything is tight. Just a quick and dirty check that setles my mind on the matter.

Also at every stop on a trip, I walk around the trailer and use the 'finger temperature test' of tire and hub of each wheel. Just another quick and dirty check that settles my mind on the matter.

[Benny K]

When I repack and reinstall bearings, I don`t use a torque wrench but spin the wheel and continue turning it and slowly tightening the nut until the turning wheel shows a resistance from the preload, I stop there and back up to the first castellation that lines up with the cotterpin hole and install the cotterpin......and like every other post so far there should be bit of freeplay in the bearings which allows for grease and heat expansion......I would think that different bearing diameters would use slightly different torques if you were using a torque wrench......Benny

[Pete Dumbleton]

My inner bearing failure (which ruined a spindle, requiring replacement of the axle) was from water-contaminated grease. I guess what happens is dirt/dust/whatever gets between the shoulder of the spindle and the rotating grease seal, grinding away the seal edges over time, allowing them to leak.

I had towed the trailer across the country (Florida to Washington) and then parked it for a year and a half. Then I left on a trip and got about 250 miles before the right wheel started jerking (likely, if I had checked temps at 50 and 100 miles, I would have detected excess heat, but I screwed up and didn't). Subsequent checking revealed the left side was also water-contaminated on the seal side. -- I don't think I would have seen it if I had just pulled the dust caps.

[Paul Riehl]

The answers given are what I was taught & have done all my life.
We don't hsve a trailer yet, but when I was growing up, my dad had me repacking bearings on all the trailers on our farm.
Some like our snowmobile trailer were repacked twice a season, because of the contamination factor.
When my Dad had his TT, the repack was done about 3-4 times a year.
He always said better to be safe than sorry, but he always carried a spare set & greese when on a trip

[Loren G. Hedahl]

What started out with a post about a cotter pin that was apparently not installed has evolved into a discussion of what is reasonable wheel bearing maintenance.

I tend to be more than a little cavalier about the maintenance, since I've only had one failure in hundreds of thousands of miles of towing. But like Paul's dad I carry spares along and tools to do the job on the road.

The one failure was New Years day in San Diego, CA. I had everything but grease. No auto parts open. I ended up using Vaseline from a local grocery store. Needless to say, I did check the temperature of that hub about every 50 -100 miles on the trip back to Washington. I also did the 'shake test' and snugged the nut up one more notch on the way home. Probably just a bit paranoid about the issue at the time.

Since it was so long ago, I don't remember if I ever re-did that hub. See what I mean about the cavalier attitude?

[Kurt in BC]

wow, look what we started!!! I gues it all depends on how the bearings sit in the hub. On my car (first gen Civic) for instance Honda calls for the nut to be torqued to 80 foot pounds ! Thats more than the wheel nuts call for! Of course on my Honda that nut is what holds on the entire hub and drums on the rear.


I think I'm going to go repack my bearings now....

[peterh]

Reviving this fine old and very related topic, I'd like to ask "How often should I repack the bearings?"

I bought my 2005 Scamp 5er in lightly used condition. Now it's two years old and going into its long winter snooze, I'm wondering if I should take advantage of this time of trailer anesthesia to re-pack the bearings or let it go for another year?

--Peter

[BobB]

Reviving this fine old and very related topic, I'd like to ask "How often should I repack the bearings?"

I bought my 2005 Scamp 5er in lightly used condition. Now it's two years old and going into its long winter snooze, I'm wondering if I should take advantage of this time of trailer anesthesia to re-pack the bearings or let it go for another year?

--Peter

Once a year is recommended, but probably not necessary. Checking the brakes is probably just as important, and can be done at the same time. I had the Casita done 2 times in 4.5 years. Still haven't done the Bigfoot.

[Alf S.]

Hi: I think that while the trailer is in "Fibernation" is a good time to do this. Better than we're all packed and ready to tow!!! Have you towed 3-5000 miles since the last repack??? Remember...a lot of things are riding on those bearings!!!
Alf S. North shore of Lake Erie

[Frederick L. Simson]

Once a year is recommended, but probably not necessary. Checking the brakes is probably just as important, and can be done at the same time.

Have you towed [b]3-5000 miles since the last repack?

I had my Fiber Stream's wheels repacked and the brakes checked the 1st time just before our Long, Long Trailer Trip of 2005. (San Diego, CA, to Syracuse, NY, to Bullard's Beach, OR, and back to San Diego, CA.) I did it again this past summer (2 years later) just before our trip from San Diego, CA, to Ardmore, OK and back. They discovered at that time that my brakes were so worn that I needed to completely replace them.

I think that Alf's recommendation to consider mileage as well as time (as a friend of mine from London says) is [b]Spot On.

My trailer had traveled over 10,000 miles in those 2 years.