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TRAILER WHEEL BEARINGS


Refuzn-To-Grow-Up

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This past trip, the right front trailer tire blew out. Exploded would be a better choice of words! The pressure monitor never gave me a warning, until the pressure was zero. We have a triple axle toy hauler.

 

As the AAA guy was installing the spare tire he said "holly smoke" and told me to take a look. The wheel had 1/4" play, when you grabbed each side of the tire (at the 3 and 9 o'clock positions) and rocked it. I asked him to let me take a closer look so I could remove the wheel bearing dust cover to see if I lost the cotter pin. The cotter pin was still there and I could not hear any crunching noise as I spun the wheel. Since it was about 20 miles to camp and it was dark, I decided to drive on. I monitored that wheel for pressure increase and there was none. I drove all the way home (about 150 miles) without any problems.

 

Today, I jacked up the front axle and removed the spare tire. I could feel the obvious "looseness" in the drum. I removed the cotter pin and tightened the axle nut (by hand) one and a half turns. Holy Crapola! I removed the axle nut and the drum and cleaned the axle stub. There was no indication of damage to the axle. Nothing! I inspected the outer bearing and the race and could see no problems.

 

Since it was getting late, I did NOT inspect the inner bearing because I did not want to pull the inner grease seal, which usually damages it. I was concerned that I could not get a replacement grease seal. The grease looked fine and there was grease present. I added more grease (I have zirk fitting on the axle) and tightened the axle nut, by hand, as I was spinning the drum. Everything seems just fine.

 

BTW - About 16 months ago, I paid a local RV shop to check my brakes and lube the bearings. I have to wonder if they did not adjust the axle nut properly.

 

Tomorrow, I will be inspecting the wheel bearings (and brake linings) on the other five tires.

 

I have never seen anything like this before. Anybody have any thoughts?

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Most people can't properly adjust a wheel bearing to save their life. Assuming it was done properly at that last service, there's the washer that is a wearing item and can cause some play with time, although that's sounds like too much for a few thou wearing off from the spinning bearing.

 

I have whole can of spare nuts at the shop so when it doesn't come out perfect...I can try another nut. After about 10 years I had to buy a bunch of new nuts because every darn nut in the can came out to the same adjustment spot!

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Most people can't properly adjust a wheel bearing to save their life. Assuming it was done properly at that last service, there's the washer that is a wearing item and can cause some play with time, although that's sounds like too much for a few thou wearing off from the spinning bearing.

 

I have whole can of spare nuts at the shop so when it doesn't come out perfect...I can try another nut. After about 10 years I had to buy a bunch of new nuts because every darn nut in the can came out to the same adjustment spot!

 

I will know tomorrow what the heck happened after I pull another hub. If I find all of them are that loose, then I guess the guy who adjusted the wheel bearings was just a dumbazz.

 

It has been years since I did this kind of work and I was actually questioning my memory . . . until I looked a few youtube vids. All of them said to finger tight, while spinning the hub, just like I remembered.

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This is a great example of why I do my own work, including packing the trailer wheel bearings once a year. It's not easy work and I can afford to hire it out, but this way I know it was done and done properly.

Greg

Greg. I am with you on doing my own work. I, too, can can afford to pay someone, but I am just going back to doing my own work . . . unless I can find someone that I can trust to do it right.

 

I am anxiously waiting for the morning. I want to see how the other hub bearings look.

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I will know tomorrow what the heck happened after I pull another hub. If I find all of them are that loose, then I guess the guy who adjusted the wheel bearings was just a dumbazz.

 

It has been years since I did this kind of work and I was actually questioning my memory . . . until I looked at a few youtube videos. All of them said to finger tight, while spinning the hub, just like I remembered.

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Dexter recommends torque the castle nut to 50# while slowly turning the hub. THEN, loosen the nut (without turning the hub) and hand tighten. The intent of the 50# is to ensure the bearings are properly seated. Might yours have been improperly seated?

 

Here is a link to their document: http://www.dexteraxle.com/i/u/6149609/f/600-8K_Service_Manual/Hubs_Drums_and_Bearings.pdf

 

Lenp

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Dexter recommends torque the castle nut to 50# while slowly turning the hub. THEN, loosen the nut (without turning the hub) and hand tighten. The intent of the 50# is to ensure the bearings are properly seated. Might yours have been improperly seated?

 

Here is a link to their document: http://www.dexteraxle.com/i/u/6149609/f/600-8K_Service_Manual/Hubs_Drums_and_Bearings.pdf

 

Lenp

 

Lenp - THANKS! Good info.

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I will know tomorrow what the heck happened after I pull another hub. If I find all of them are that loose, then I guess the guy who adjusted the wheel bearings was just a dumbazz.

 

It has been years since I did this kind of work and I was actually questioning my memory . . . until I looked a few youtube vids. All of them said to finger tight, while spinning the hub, just like I remembered.

 

Refurz-To-Grow-Up,

 

I know you don't want to hear this. Knowing myself, I would want to know what that inner bearing looks like. That means removing the wheel and wheel seal. A good parts place should find that seal for you by cross referencing the part number that is on the seal that you have for the trailer. Clean up both bearings, inner and outer and inspect the rollers. If things look good, hand pack the bearings with wheel bearing grease. To jar your memory on packing bearings, you can always use You Tube for your research. I would not use the zerk fitting to pack the bearings. The reason that I say that is because you need to get the grease in between the rollers. I know this means extra work but for peace of mind I think it is worth it. At least for me it is.

 

Good luck,

Al

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Strange that the tpms didn't give you any indication that the tire was at least heating up (presuming your tpms fires give you a temperature for each tire). If the wobble on the wheel was responsible, one would expect at least the tire heating up before blowing out...

 

Assuming you mean that one tire would have a significantly higher temp than the other tires.

 

It really depends on the type of TPMS. The TPMS sensor on the valve stem is very ineffective with measuring tire air temp. That style is "in the wind" far away from tire/hub heat. Even the sun beating down on those type of sensors affect it's temp reading. The internal type would be better for measuring actual tire air temp. But even then, if the hub is heating up, air flow over the wheel reduces the air temp inside the tire relative to a heated hub.

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Tire air temp is fairly accurate to a point on the TST units but it has no real perfect relation to the tire tread temp you take with a temp gun. Except looking for that odd man out.

 

If you are running alluminum wheels they are one large heat sync. A lot or the bearing temp is dissapated quickly so not easily picked up in air temp.

 

We had a brake caliper on the trailer not releasing fully. Noticed no huge increase in air temp but after 30 min drive stopped and felt extreme heat at one wheel. Took gun reading of the wheel and it was 100 degrees hotter then others.

 

Hit the tires and hubs on the rig with temp gun at all stops is a good measure.

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Thanks everyone for your input.

 

I just told the DW that we need to cancel our traditional Christmas trip (we were due to leave in a few days). I am running out of time to S A F E L Y get to the bottom of this bearing issue. I prefer not to have any more drama in my RV'ing life.

 

Al: I am taking your excellent advice and I will be pulling all of wheels and removing all of bearings for a thorough cleaning and inspection. I am trying to locate the recommended grease (see link in post #7). I think that I have Dexter axles.

 

I dug into my tool archive locker and I have a cone-shaped tool for filling bearings with grease, using a grease gun. Or, I may use the glob of grease in the palm technique that I learned as a kid.

 

For those of you who are wondering about temperature monitoring. It has been a while, but I think temperature and pressure, in a closed vessel (like a tire), are directly related (Boyle's Law??). So if temperature increases, so will pressure and vise versa. I have had tread separations and the pressure monitor gave me an early warning. In a tread separation, I am guessing that the tire temperature increases and this will cause an increase in tire pressure, which sounds the alarm.

 

This tire exploded instantaneously into pieces. We were close to a navy base and when we heard the loud boom, we thought that the pilots were making practice bombing runs, until we saw "0" on the pressure monitor.

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With that much play, the tire had to running significantly out of alignment which would have put a ton of stress on the tread and belts of the tire ultimately causing it to come apart. I would certainly think that the stress would have shown up on the monitor as the tire inevitably heated up prior to letting go. Perhaps you need to look at your heat alarm setting on the tpms display, the tire may have been significantly hotter than the other 5, but not reached your alarm preset. Maybe you need a lower alarm setting.

 

Likely the installer simply did not get the bearing seated properly when installed on the last go round, I've always said that properly tightening a bearing is more art than science. Still, if it had been running a bunch of mile out of adjustment I'd replace the all of the bearings on that hub just as a precaution, bearings aren't that expensive, and I would certainly expect some unusual wear on them from that situation.

 

I ALWAYS carry spares. Every trailer I own has a box with a complete spare hub/drum filled with a full set of pre-greased bearings and seal all in place ready to slap on by the roadside if needed. Also an entire extra set of loose bearings, washer, nut, a couple of pins/clips, and a few seals and a grease cap. Trailer axle parts can be VERY hard to find depending on where/when the thing decides to break down, so I make sure I have the stuff to fix it right there if need be. $100 at you local trailer supply for a box of spares is cheap insurance against being stranded in my book. I don't bother with (electric) brake parts for spares, in the highly unusual circumstance that the shoes etc become damaged from a bearing issue, I can simply pull off the shoes or entire backing plate and cut the wire to that hub and run just fine with 5 brakes til I get where I am going.

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Right rear tire had the same amount of "slop" as the right front tire. The bearing nut, like the one on the right front tire, was exactly 1 and 1/2 turns too loose. I did not bother to inspect the other four wheels. I went on to repair damage done by the "RPG" that struck the underside of the chassis.

 

I measured the bearings and wrote down the part number for the grease seal. I am going to replace all bearings, all seals and grease. I have a friend, in the machinery repair business who is expert in bearings and seals. Time to give him a call and ask for help.

 

I have three Lippert 6,000 pound axles.

 

Hot Rod - good advice. I will include spares in my order. Regarding temperature setting. Regarding temperature limits, I set those up. DAAHH! I need to go back and see what I did.

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Refuzin, we have had tires blow that never gave any warning on the tire monitors until they blew. We heard the explosion first.

 

We have also had our bearings loosen up too and we repacked them ourselves. We have a triple axle toy hauler with 5200# axles. We keep spare bearings, seals and a bearing packer and grease in our trailer.

Dave

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I'd be willing to bet that whoever you had pack the bearings the last time did so with the wheels on the ground. That will produce the effect you're describing exactly. Usually all on one side. (I know that because I caught a shade tree doing that to an old truck I had...)

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The way I was taught to adjust wheel bearings was to tighten down the nut while spinning the tire as tight as I could go and back off 1/4 turn. At the top of the tire push in and out. Tighten and loosen the nut until you can feel play In the tire. Tighten the nut enough to get the play out and your there. If the hole doesn't line up, I will back off to the hole and insert the cotter key. You DONT want a over tightened bearing. The key is to adjust it until you don't feel any movement. A slightly loose bearing will run a lot longer then a over tightened one.

Everyone has their own way of doing things, but this way has served me well for over 40 years and I have adjusted a lot of bearings.

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Being someone who cannot accept something that does not seem right (like wheel bearing nuts 1.5 turns too loose), I started an early morning quest to find the answer to loose bearings, which is slightly better than loose bowels, after stopping at a roadside diner for lunch. From that day forward, I always "brown bag" meals, while on the road, but I digress..

 

During my quest for the truth, I discovered that there are many techniques to adjust wheel bearings and all of them get to the same desired result, which is, seat the bearing races in the hubs, bearing preload should NEVER be too tight and bearings should not be so loose that the wheel wobbles. Always error on the loose side, when preloading bearings. And, for the purist, the cotter pin hole is NEVER in the right location. So better to back off the nut and leave bearing preload a little loose rather than too tight. Regarding the cotter pin hole in the wrong location: The wheel bearing nut threads are all coarse (fine would seem to be better). There are shims that one can buy (McMaster Carr comes to mind) to get the preload perfect. One fellow takes the nut to his belt sander to remove material from the bottom of the nut to get preload perfect. And, I thought that I was picky. :rolleyes:

 

Apparently, I am not the only one who has experienced this loose nut problem. It seems to be common in both the RV and the boating community. How could this be? Bearings are finely made machines. As a young machinist, I marveled at the dimensional accuracy of bearings. I struggled to comprehend the hardness of the races, balls and or rollers, and was mesmerized by the shininess of the contact surfaces. My boss told me that (at the time, which was a few decades ago) that all of the bearings were metric because they were invented in Europe (Germany, I think, but not sure anymore).

 

I continued to search these threads and finally, one old timer came up with what appears to be the answer to the loose bearing problem and it is one word. The axle makers are buying their bearings from, . . . . you guessed it . . . . . C H I N A!

 

So, I am guessing that the cheap, poor quality china crap bearings are not up to the task of the carrying the huge loads that we place on the wheel bearings and they are wearing out. Since these are tapered bearings, when the bearings wear out, they become loose.

 

So, when I replace my bearings, I will be doing so with non-China made bearings, if that is even possible anymore. :( I know that I will pay more, but that is better than sitting on the side of the road with a destroyed bearing and axle stub.

 

That is my morning coffee rant. Safe travels and I will let you know if I can find non-china bearings.

 

Growing older each day, but Refuzn-To-Grow-Up

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So....re-fuse, your fuse seems to be simmering this morning ..... maybe some Dr Pepper is in order.

 

So I drop of a alternator off at Huston's shop for him to install a new belt pulley and then we get called away for mom in law matters.....a few days later I get back to the Dollytrolley shop and there on the bench was the alternator with the new pulley installed ....AND....a pile of NEW Tempkin bearing boxes and all of the "export" bearings from the Dolly-toyhauler were in the trash barrel....no need to discuss anything with Huston ....he is a Geezer and he only stocks the best bearings...Period!!

 

Every year I pull the trailer hubs and service the dorky electric brakes and Huston's bearings still have original grind marks on the races....

 

Not ever been able to calculate the savings from substandard bearings....

 

Drive on....(Huston won't sell junk...)

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Replaced my Dexter NevRLubes all around. Won't go into that debacle. Anyway ordered the new bearings direct from Dexter. Etrailer and some other places sell one called Redline made in China. Bearings arrived- Made In China. Original ones stamped with made in Spain. Quality definitely different. When I called Dexter they were indignant that I questioned the quality of their bearings and that they were thoroughly tested-yeah right! We shall see.

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Dolly: The china crap flooding our market really gets under my skin. Can ya tell?

 

Years ago, I had a welding project and was using some (unknown to me) china steel. I could not run a bead to save my life. Checked the welder settings, cleaned my glasses and tried again. Then I saw the tiny "made in china sticker." So, I pulled out a piece of steel from the scrap bin and ran a perfect bead. When I took the steel back to my supplier, the salesman called the owner and said, "We have another batch of bad steel." Never went back to the place again!

 

Suite: Get rid of the china crap bearings or you will be changing bearings on the side of the road, some day. If those dumbazz china companies cannot make weldable steel, I am guessing they do not have a clue how to make heat treated bearings. And, years ago, all of the American manufacturing companies were taken over by "bean counters" with MBA's, so they would not know a good bearing if it bit them in the butt!

 

I need to go back to work and make some money. :rolleyes:

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