This Flat Makes Me Mad!

[Allan in NE]

Venting.......

Went out to check the trailer over today.

Just paid good money a year ago to have the brakes checked and bearings all repacked and so forth; haven't pulled the thing over 300 miles since.

I ABSOLUTELY HATE THE GUY THAT STARTED THE RUMOR THAT YOU ARE SUPPOSED TO "BACK OFF" THE WHEEL BEARING PRE-LOAD ADJUSTING NUT.

Yep, every darned one of 'em is loose. Now, I gotta do all that before I can even hook up. That really torques me off!

Guess if ya want something done right, ya gotta do it yourself. :>(

Allan

 

[PH]

I have always tend to question that theory myself!!!! Does anyone have there own ways on tightening bearings?

 

[ericlb]

allen, i think your right on, no use paying somebody to do a job wrong, i do all my stuff myself for just that reason, seems like everytime i hire a shop to do some repair work, i have to go back and fix their repair myself anyway, on wheel bearings, i tighten the bearing nut while spinning the wheel assembly, then tighten or loosen the nut to the nearest slot to insert the cotter pin, however this isnt always right for instance the front wheel bearings on my big truck have a torque that that must be tightened to, and i dont remember right now what it is, but its pretty tight

 

[Dairy Farmer in WI]

don't ya just hate the people that think the RIGHT way is the wrong way? when i was 15ish i worked on a dairy farm downt he road. my bosses grandson thought everyone else was wrong or had the wrong way of doing things. needless to say he got B-ed at a lot and broke many thing that i had to fix because of HIS ways.
have a good one
DF in WI

 

[tlak]

The link is a variation on how I do it. Usually crank it tight first, then back it off felling the spin of the wheel and still tension on the nut, then get it to the nearest cotter key hole.
interesting

 

[Allan in NE]

Well sure,

After the bearing/hub is correctly repacked and reassembled, the tire/wheel is rotated by hand while torquing the nut to 12 ft lbs (depending upon the size of the bearings, of course).

If the keyway lands "between the grooves" ya continue to tighten to the next groove and until the key can be inserted. Under no circumstances should the preload be released and if assembled this way, they will darn near run forever.

That old fashioned "back it off" theory is a hand-me-down from the days of ball bearings and is an absolute "death warrant" for a tapered roller bearings. They will then in time and with use, wear/loosen and the entire load only rides on the "edge" of one roller at a time instead of being distributed evenly across the entire bearing surface(s).

I dunno. Trouble is, 'bout 80% of the guys with wrenches still back 'em off just as they did all those years ago.

I should have stood there and watched them do the job I guess. :>(

Allan

 

[Anonymous-0]

Allen needs to read up on what bearing manf recommand as a correct to install brgs.

they want "0" perload on a tapered brg.

I havent yet seen a service manual that tells you to perload a tapered wheel brg

 

[Allan in NE]

Whoops, 81%. :>)

Allan

 

[Coloken]

Allan, your right unless it a 1936 Chevy. As far as I know, every tapered bearing in transmissions are pre-loaded.

 

[Allan in NE]

Oh Heck Ken,

Don't know if I'm right or not, but I darned sure know what lasts and what doesn't.

Just one of the perks of being old. :>)

Allan

 

[Janicholson]

Well me thinks (without malice) that you have seen too few manuals. Backing off is not the point, preload of correct magnitude is essential. There are 15 ways to get there, from shims to crush sleeves and nuts with lock nuts, but W/O specified preload a tapered roller pair is sure to die a regretful death. There may be an application with zero preload if the operating conditions heat the system in a way that puts preload into the set when at temp, but it will be there. JimN

 

[george md]

Allan,

bearing manufacturer says tighten nut to

50 ft lbs of torque , then back off 1/6 of a

turn.

Some where here I have the step by step

procedure from bower/ bca for assembling and

tightening tapered roller wheel bearings.

george

 

[trucker40]

I didnt know that,they taught me the back off way in that link.Does that work on big trucks and trailers?

 

[Allan in NE]

Gotta disagree with ya on one issue Jim.

Without naming names, our buddy, "Me Thinks" is VERY well informed and is an absolute, killer, outstanding wrench. He is a very knowledgeable guy.

He and I have had this discussion before.

However, I would submit that manufactures are in the business of SELLING bearings and for darned sure not actually in the nature of prolonging their useful life.

Heck, what's a little oversight/misprint here and there in the old tech manual amongst friends?

Just a slight variation on the old “built in obsolescence” theme? You know, let's make ‘em go “Just long enough”?

Pretty slick marketing, I'd say.

Allan

 

[steve in wi]

I'll have to agree with you allen,when doing IH differentals and axles they always require preload on the bearing,and they are tapered rollers. Put many bearings in those red tractors,and they all required preload.Those goose neck trailers tires don't need any more movement than they go thru. Just my 2 cents if thats worth anything. Steve in wi

 

[Bob]

Allan,

Have to disagee with you.

A friend of mine thought as you do. EVERY wheel bearing he serviced, he "pre-loaded", starting with his own 1979 Ford pickup.

He was going on a trip, and re-packed his front wheel bearings (4 X 4), and was PROUD of snugging them up. One side failed within 100 miles, and the other before he got back home.

He wound up working at the local Cenex, and our shop got to haul in and repair several trailers and medium-duty trucks he had "pre-loaded" the wheel bearings on.

At our shop, we have always followed manufacturer's instructions when available, or set up wheel bearings WITHOUT preload, and I can't recall even ONE single instance where we have been asked to warrantee a wheel bearing job, or EVER heard of one of our jobs failing.


YES, you preload differential carrier side bearings or pinion bearings, but that is a different matter, altogether. In MOST cases, those bearings are a different series, with a different angle to the rollers and races.

I have yet to see a single manufacturer's instruction to pre-load a set of tapered roller bearing wheel bearings.

WHY are you complaining about the job the guys did on your trailer... have ANY of the bearings failed???

 

[Anonymous-0]

You are right Allen; no tapered roller bearing should operate in a loose condition. To properly set tapered roller bearings so they run with no looseness is sometimes difficult when heat and expansion is involved. On tractor front wheel bearings, we tightened the adjusting nut to about 20 ft-lb and installed the cotter pin. The Timken rep about had a fit, but they didn't run fast enough to get hot and would last for years and thousands of hours. Transmission bearing settings are more involved. Your trailer bearing settings are relatively simple. They should not ever be loose, but should not be set so tight that they get hot and burn up. A very light preload always worked for me on trailers that are pulled 50 to 80 mph. But you are right; they should never operate in a loose condition.

 

[mowr]

Manufacturers give a preload torque spec from zero on up for a tapered roller bearing on a non-drive axle, based on several things. Some are: size of bearing/load capacity, whether bearing is packed or runs in oil or gearlube, and the number of threads per inch on the spindle and nut. When a bearing burns out and someone gets hurt, people sue. So it's in the manufacturers best interest for the engineers to determine the specs that will give the best chance of long bearing life and

 

[mowr]

in the owner's best interest to follow the manual. Perhaps everyone who posted here with very different figures is correct for the applications they are referring to.

 

[Anonymous-0]

Yep that's as bad as when neighbors borrow your trailer and always bring it back with flat tires.