Stripped a front hub! Why?

[Flowmastered87GL]

The car: 1987 GL 4WD Wagon, EA82. 318,000+ miles, original hubs and suspension junk.

 

Condition at time of failure:

 

New CV's (less than 1 year old)

Junky brakes, pads are ok, but e-brake sticks if applied and rotors are warped.

 

Basically what happened is I went to pull out of the parking lot at work and the car didnt move in 2WD, found out a CV was spinning but the car was going nowhere.

 

So... limped it home in 4WD.

 

Took everything apart, sure enough ALL the splines in the right front hub are gone!

 

I was able to remove the axle nut on the passenger side (after taking out the cotter pin) with very little effort, it was like finger tight.

 

Now... with the pin in there, how could it get so loose?

 

Is it possible that when I did the CV's I didnt tighten it right or something? The washers WERE installed correctly and were approved by a second person as being right.

 

Could the horrible state of the brakes have caused this somehow?

 

Everything is replaced and works good now (only took like 3 hours) and I saved the extra good hub just in case. But I want to make sure this doesnt happen again.

 

I plan to check the axle nuts in 3000 miles just to make sure its all staying together.

 

So... any guesses as to why this stripped out? Was it just the hubs time?

[GLCraig]

Have you been spending too much time in 4wd on the pavement?

[edrach]

Probably dirt or stuff on the backside of the hub letting you tighten down to the proper torque. Then as the dirt and stuff came out, the "nut came loose."

[Ross]

Did the hub look corroded at all?

 

Also, was the thread on the end of the stub axle stripped as well?

[pat hutt]

driving in 4wd on the pavement is very hard on all the running gear and if the axile bolt was a little loose and enabled a little play can damage it very very fast luckie u were in a subie aye mate otha wise u would of been pushin..

[NV Zeno]

Mike, were there noises coming from there before it failed? I've got a feeling mine is just about toast too.

[MorganM]

It has 318,000 miles on it.... replace that one and the other side!

[Flowmastered87GL]

Noises before it failed... YES! tons of em.

 

Both sides have been replaced, still have some noise.

 

Do I run 4WD on the pavement... yes, but generally in a straight line, or when pulling out into traffic in the rain from a hill (very easy to spin tires there, need 4WD go get moving)

 

100,000 + miles of me driving the car, rallycrossing, drag racing ect probably just took its toll.

 

For now the car is good, gonna check it shortly, maybe even use an air wrench soon to make sure everything is good and tight.

 

Maybe even have Richie to a full suspension inspection so a trained eye can make sure everything else under there is ok.

[subynut]

Ya know, I've had mine work they're way loose after about 50 miles after a replacement too. I usually have to re-torque them about twice before they stay put. My driving is rather rough too: fast take offs, lowrange take offs at lights, drifting on dirt roads in 4wd, things of the sort. My first sign that the hubs are loose is my brakes start making funny sounds when I turn. Re-torquing the castle nut solves it.

[WJM]

had one do that on my RX...the wheel bearing was bad on that side as well...didnt hear the noises of the bearing until 5k miles later.

[Buddy]

i have no idea why but the exact same thing happen to my dad THREE times last year. first it was the LR side then a week later the right rear side. then two weeks later the RF went out. it was crazy those three times because the three times the car broke down was in San Jose where he worked. we live in Manteca and he was about 100 miles from home. so there i go with my mom to the "rescue" and fortunately the car came home on its own the second and third time. the first time he drove it home the 100 miles going 25mph on the freeway with the car fishtailing two times and the brakes going out on a steep downhill curve with the cliff in front of us.

[Urabus-84HBDR]

My 84 Hatch did the same thing, I pulled out into traffic, 2wd just pulled to the left, man I love 4WD in my CAR, saved me more than once. Took my tire n hub off and sure enough stripped. Got one from the local junkyard, put it in and been driving ever since. Only a little bit of noise, when I'd go to take off it would growl, or klank, weirdly, I dont drive too much in 4WD, only off-road. What else would do this, I have also checked my axle nut to make sure its torqued right. I dont have many other ideas for this problem.

 

83 Wagon EA-81 D/R 166k, ticking away,

84 Hatch EA-81 D/R 144k, counting

86 Wagon EA-82 AT, 142, parked:(

[archemitis]

happened to my buddy goin up a hill in an spfi subaru, 2wd. the car was carrying one 300lb driver. 4 passengers that weighed 150+each. stripped right out. wierdest thing i have ever seen.

 

my ea81 2x would come loose about once a month, three times, never spun the splines off tho.

 

i always figured it was from incorrect install... but i pound em on with a hammer, so i doubt that =/

[KStretch55]

Have you checked your wheel bearings lately? I had nearly the same happen to the right rear on my '91 wagon, except I heard it rumbling and caught it before the splines were completely gone. The rumbling always stopped when I applied brakes, and I was constantly re-torqueing that particular axle nut.

 

Here's my theory: If you have one that won't stay tight and you know that you installed everything correctly and torqued it to specs, and you still keep finding it loose. It's time for new bearings. I think the bearings get worn excessively, either due to lack of grease or just a lot of miles. You torque the nut down and everything is tight, until the bearings wear more and then everything gets sloppy. The slop allows the drum or rotor to wobble on the splines, which wears them off rather quickly. That's my guess, anyone else?

[archemitis]

i thought about this too, but when you look at it, all of the torque goes onto the center sleve, and the inner bearing races. the only way i could see that bad bearings could do that is if they siezed , and spun in the hub. then it all goes bad.

[KStretch55]

That's a good point and one I had considered, too. So, I'm guessing that either continual retorquing causes the spacer between the bearings to wear somehow and then the load is transfered to the rollers and races, or after 100,000 miles or so the bearings just begin to get worn and allow the hub to wobble. The wobbling just works the nut loose. What ya think, most likely the later?

[Do It Sidewayz]

Without a doubt the reason the hub stripped is because the big axle nut wasn't tight enough.

 

 

What happens is the little conical washer will start to spin over time, and wear itself down. So the axle loosens itself off, but you don't see it because the nut and pin stay in the same spot. Now...the axle is a little loose and the splines will have some play in the hub. The CV is made of a VERY hard material, and once you get a little bit of play in the splines the hard CV splines will wear away the VERY soft Cast Iron splines on the hub. In no time the splines become "sharp" and then they just cannot hold the torque any longer.

 

There's two things you can do to help prevent this.

 

First: When you install the new CV, make sure both of the splines are clean and free of burrs. Then apply grease to the slines, not only will this make it easier to install, but will also stop the splines from wearing if the washer happens to wear again. Also grease the Conical washer, it will stop it from wearing.

 

Second: Make sure the things are VERY tight....often times even and impact gun is not tight enough....I always run them on with the impact, then put the car on the ground, get a friend to put the car in 5th and stand on the brakes. I use my breaker bar, and get them as tight as i can. you can usually get atleast 1/8 to 1/4 turn more.

[Ross]

I use loctite spline lock when installing the hub, this prevents anything like this happening. It does mean that you need to use a puller to get it off, but IMO thats no big deal.

 

I strongly recomend using loctite if your hub splines look the slightest bit damaged. If there is any considerable slop in the splines, no matter how tight you torque the hub nut, they will wear very quickly.

[CIS Subaru]

Do it Sidewayz has it absolutely correct.

 

I had a '83 2wd Sedan that suffered from repeated loose axle nuts. I noticed it because of the brake noise in turns (dragging when the brakes were not applied). I kept tightening the nut, only to have it loosen up on me a week or so later. It turned out that the cone washer was wearing down. I replaced it with a good one I picked up at a junkyard, made sure the nut was tight, and the problem never returned.

 

If I remember correctly, don't the torque specs for the axle nut say to tighten to 150 foot pounds and then TIGHTEN MORE until you can get a pin in? I always stand on my 18" breaker bar and bounce a little until the holes line up. That seems to work just fine. I've sometimes wondered what it would take to actually overtighten these things.

[subynut]

If I remember correctly, don't the torque specs for the axle nut say to tighten to 150 foot pounds and then TIGHTEN MORE until you can get a pin in? I always stand on my 18" breaker bar and bounce a little until the holes line up. That seems to work just fine. I've sometimes wondered what it would take to actually overtighten these things.

 

 

I got a 24" breaker bar for tightening the castle nut. Works quite well.

[NV Zeno]

I have a question...when the hub was removed and found to be worn, were the splines on the axle also messed up?

[Qman]

There are actually a number of correct answers for this. Axle shaft spline length, bearing condition, hub and axle shaft spline condition, and actual torque applied to the axle nut.

 

Axle shaft spline length;

 

There are different length splines depending on where the core axle came from. They all fit, but will not all fit correctly.

 

Bearing condition;

 

The bearings are the biggest contributor to worn/stripped hubs. Before those who say no jump up screaming think about it. When bearings wear the front tires wobble, correct(rear as well for that matter)? Why is this? If the axle held it all tight the bearing would never cause slop to appear, correct? The hub is not designed to bottom out on the splines. That is why they end in a point on the axle and are not square grooves. The bearing takes up the slack. If the bearing is not adequately greased or is starting to fail it will continue to loosen until it finally does bottom out on the axle. Then, the wear to the shaft and hub begins.

 

Hub and axle shaft spline condition;

 

This is directly related to all of the above. Also, hubs and shafts that are exposed to alot of the elements, snow, mud, rain, and overall dirty conditions will also wear out sooner than those that are not.

 

Actual torque applied to the axle nut;

 

I believe that the torque requirement for axle nuts is around 140 ft/lbs. Now how many people just jump on top of their breaker bar and/or extension to get them as tight as they can? What would happen if you used this procedure for head bolts or intake bolts or the front crank bolt? The threads would stretch. As the threads stretch they are no longer able to hold the torque applied and appear to loosen.

 

Draw your own conclusions as I know most will. Bottom line is do the repair correctly or keep doing it over and over again.

[subynut]

Point taken, Qman. I'll be less torquey on my breaker bar next time.

I'll also check my washers and see if they are worn out. Prolly are since I have never replaced them in all the half shafts I've swapped in the six years I've had me Suby.

[Flowmastered87GL]

Interesting update:

 

Had to get 2 new tires today (one bald and another had a razor blade in it :-\ )

 

Anyway, the right front axle nut was loose AGAIN! (I snuck in the bay at Les Schwab and checked it when the wheels were off.)

 

I asked them to snug it up for me.

 

I'm going to replace the conical washers on it and see if that helps.

 

Will keep updating as this problem progresses.