Brand new hub stud failure and subsequent damage

Sensei · Oct 2, 2024

Just finished putting together a project jeep I acquired a couple months back and took it wheeling for the first time. Coming back from the trip (less than 10 mile drive) and driving around the next day I started hearing a banging noise from the front end and the brakes seemingly start to grab. I thought it was my new Spartan locker engaging and disengaging at odd times but decided to jack up the front end to inspect. What I found was my driver side wheel about to fall off. Upon closer inspection, it seems one of the studs on my brand new timken hubs has broken off, and left some damage in its wake. I also noticed the remaining 4 lug nuts to be loose, even though I'm certain I torqued everything to spec twice, once in the air and once on the ground. As a result of the lug nuts loosening up, all the threads on the studs that remain are severely mangled. My new rotor is chewed up and cracked from the piece of stud that fell out the back of the hub. And my hub mounting bolts have been sheared at the ends in two of the three bolts. I just wanted to share my experience and see what others think the main culprit for the failure was. Can one stud breaking off really cause the whole wheel to loosen in less than a total of 20 miles since installation? Is it really possible I left the lug nuts loose? Or maybe I overtightened this one causing it to eventually snap? There really was no early indication that things were loose. It was wheeling perfectly fine on some tough terrain. The tires sat square on the pavement. The tires didnt wobble at all. Then I heard that bang the next day or so that I thought was my locker and things started acting and looking funny. Attached are some pictures of the damage, and the remains of the snapped hub stud. I've already ordered parts to get everything fixed, just wondered what others thought about how this problem started.

Sensei · Oct 2, 2024

More photos

lBasket · Oct 2, 2024

Idk if this is it but shitty parts are starting to get pretty common

AndyG · Oct 2, 2024

Might be a good one for @mrblaine to tell us what he sees- The studs look plenty long- I’n curious if your lug nuts may have bottomed out on the end of the stud rather than the wheel.

Watch aftermarket wheels on the rears of rubicons too- trust me.

Sensei · Oct 2, 2024

AndyG said:
Might be a good one for @mrblaine to tell us what he sees- The studs look plenty long- I’n curious if your lug nuts may have bottomed out on the end of the stud rather than the wheel.

Watch aftermarket wheels on the rears of rubicons too- trust me.

Someone else mentioned this same thing to me in person and definitely a good variable to check, but I actually took the wheels and tires from my other jeep, as well as the lug nuts. I even measured the stud lengths to ensure everything was the same. It's all identical. I thought maybe I cross threaded the lug nuts when I installed them, but the ends of the studs are perfectly clean. The hub is TIMKEN HA597449, so it should be right.

mrblaine · Oct 2, 2024

lBasket said:
Idk if this is it but shitty parts are starting to get pretty common

I don't see anything that says these are shitty parts. I see major hints of an installation error that was overlooked or missed somehow, but nothing that says the parts are crap. Something broke the stud, not sure what and not sure how a single one breaks unless it got overtightened but that was where it started. It broke, worked inward, piece hit the end of the knuckle bolt, that broke that off, cracked the rotor edge, wallowed around in there and did the rest of the damage.

Note the use of the phrase "major hints" because that is all it is.

mrblaine · Oct 2, 2024

AndyG said:
Might be a good one for @mrblaine to tell us what he sees- The studs look plenty long- I’n curious if your lug nuts may have bottomed out on the end of the stud rather than the wheel.

Watch aftermarket wheels on the rears of rubicons too- trust me.

If the lug nuts bottomed out, all of them would have been loose and probably broken after being driven that distance. That also destroys the rim in very short order.

mrblaine · Oct 2, 2024

Sensei said:
Someone else mentioned this same thing to me in person and definitely a good variable to check, but I actually took the wheels and tires from my other jeep, as well as the lug nuts. I even measured the stud lengths to ensure everything was the same. It's all identical. I thought maybe I cross threaded the lug nuts when I installed them, but the ends of the studs are perfectly clean. The hub is TIMKEN HA597449, so it should be right.

The stud threads can be good and still have cross threaded lug nuts.

Sensei · Oct 2, 2024

mrblaine said:
I don't see anything that says these are shitty parts. I see major hints of an installation error that was overlooked or missed somehow, but nothing that says the parts are crap. Something broke the stud, not sure what and not sure how a single one breaks unless it got overtightened but that was where it started. It broke, worked inward, piece hit the end of the knuckle bolt, that broke that off, cracked the rotor edge, wallowed around in there and did the rest of the damage.

Note the use of the phrase "major hints" because that is all it is.

So you're leaning towards the stud being overtightened? It does seem to make the most sense in this situation. Maybe the stud wasn't fully seated from the factory? The spline looks a bit beat up where the stud seats into it, but I suspect thats probably from the wallowing around.

lBasket · Oct 2, 2024

mrblaine said:
I don't see anything that says these are shitty parts. I see major hints of an installation error that was overlooked or missed somehow, but nothing that says the parts are crap. Something broke the stud, not sure what and not sure how a single one breaks unless it got overtightened but that was where it started. It broke, worked inward, piece hit the end of the knuckle bolt, that broke that off, cracked the rotor edge, wallowed around in there and did the rest of the damage.

Note the use of the phrase "major hints" because that is all it is.

It might just be fresh in my mind because I'm dealing with bad NIB parts in my other project

mrblaine · Oct 2, 2024

Sensei said:
So you're leaning towards the stud being overtightened? It does seem to make the most sense in this situation. Maybe the stud wasn't fully seated from the factory? The spline looks a bit beat up where the stud seats into it, but I suspect thats probably from the wallowing around.

This ring made by the head of the stud says it was probably installed to full depth.

One stud breaking won't cause this, this is caused by the lugnuts not being tight based on the aluminum in the threads of all the studs. That's from the rim wobbling around and that is what likely caused the single to break.

Sensei · Oct 3, 2024

mrblaine said:
This ring made by the head of the stud says it was probably installed to full depth.

One stud breaking won't cause this, this is caused by the lugnuts not being tight based on the aluminum in the threads of all the studs. That's from the rim wobbling around and that is what likely caused the single to break.

Does the paint or coating on the front of the brand new rotor indicate anything to you? To me it looks like the rim was seated enough to make solid contact and wear the paint with heat generated from braking. I feel like if the wheel was loose I'd see more uneven wear of that coating wouldn't I?

mrblaine · Oct 3, 2024

Sensei said:
Does the paint or coating on the front of the brand new rotor indicate anything to you? To me it looks like the rim was seated enough to make solid contact and wear the paint with heat generated from braking. I feel like if the wheel was loose I'd see more uneven wear of that coating wouldn't I?

The studs full of ground up aluminum tells you the wheel was loose at some point. I've seen many rigs with 4 studs driving just fine. That says that a single missing stud doesn't let the others fail. It is all guessing after that.

What pushed the stud back far enough to make contact with the end of the bolt and snap the stud in half?
If the nut was tight, threaded on all the way and the stud then broke in half, what pushed the piece left in the flange back that far? There are tons of examples of broken studs out there, the piece always stays in the flange. Something pushed it back with enough force to overcome the press fit. I would guess the wobbling rim could do that if the lug nut is a fairly close fit in the hole in the rim. Lug nut half way out, rim wobbles, breaks the press fit, stud moves back, catches the end of the unit bearing bolt, snaps it off and the piece with the lug nut goes bye bye.

A peek at the lug nut bores in the rim will tell you if the rim was wobbling enough to hit the lug nuts on the sides of the holes.

Sensei · Oct 3, 2024

mrblaine said:
The studs full of ground up aluminum tells you the wheel was loose at some point. I've seen many rigs with 4 studs driving just fine. That says that a single missing stud doesn't let the others fail. It is all guessing after that.

What pushed the stud back far enough to make contact with the end of the bolt and snap the stud in half?
If the nut was tight, threaded on all the way and the stud then broke in half, what pushed the piece left in the flange back that far? There are tons of examples of broken studs out there, the piece always stays in the flange. Something pushed it back with enough force to overcome the press fit. I would guess the wobbling rim could do that if the lug nut is a fairly close fit in the hole in the rim. Lug nut half way out, rim wobbles, breaks the press fit, stud moves back, catches the end of the unit bearing bolt, snaps it off and the piece with the lug nut goes bye bye.

A peek at the lug nut bores in the rim will tell you if the rim was wobbling enough to hit the lug nuts on the sides of the holes.

Yikes. I find it hard to believe I left the lug nuts loose, but the evidence is pretty compelling at this point. Very happy I caught it "in time" atleast before anything catastrophic or deadly occurred. Any suggestions or good ways to repair my wheel?

mrblaine · Oct 3, 2024

Sensei said:
Yikes. I find it hard to believe I left the lug nuts loose, but the evidence is pretty compelling at this point. Very happy I caught it "in time" atleast before anything catastrophic or deadly occured. Any suggestions or good ways to repair my wheel?

View attachment 562963

You can repair it, the cost is likely higher than another wheel. What wheel is that?
You can get a set of these, get the wheel machined to accept them and then press them in. Restores the taper and should get the hole fairly well cleaned up.
https://www.ebay.com/itm/1129540710...pid=5337789113&customid=&toolid=10001&mkevt=1

Sensei · Oct 3, 2024

I believe this is the wheel. Those inserts seem interesting, if I can't source a new rim I'll consider that route.

Rickyd · Apr 13, 2025

Sensei said:
Just finished putting together a project jeep I acquired a couple months back and took it wheeling for the first time. Coming back from the trip (less than 10 mile drive) and driving around the next day I started hearing a banging noise from the front end and the brakes seemingly start to grab. I thought it was my new Spartan locker engaging and disengaging at odd times but decided to jack up the front end to inspect. What I found was my driver side wheel about to fall off. Upon closer inspection, it seems one of the studs on my brand new timken hubs has broken off, and left some damage in its wake. I also noticed the remaining 4 lug nuts to be loose, even though I'm certain I torqued everything to spec twice, once in the air and once on the ground. As a result of the lug nuts loosening up, all the threads on the studs that remain are severely mangled. My new rotor is chewed up and cracked from the piece of stud that fell out the back of the hub. And my hub mounting bolts have been sheared at the ends in two of the three bolts. I just wanted to share my experience and see what others think the main culprit for the failure was. Can one stud breaking off really cause the whole wheel to loosen in less than a total of 20 miles since installation? Is it really possible I left the lug nuts loose? Or maybe I overtightened this one causing it to eventually snap? There really was no early indication that things were loose. It was wheeling perfectly fine on some tough terrain. The tires sat square on the pavement. The tires didnt wobble at all. Then I heard that bang the next day or so that I thought was my locker and things started acting and looking funny. Attached are some pictures of the damage, and the remains of the snapped hub stud. I've already ordered parts to get everything fixed, just wondered what others thought about how this problem started.

View attachment 562753 View attachment 562756 View attachment 562757 View attachment 562754 View attachment 562755

It is good practice to torque your wheels again after going for a drive. Especially with alloy wheels

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Brand new hub stud failure and subsequent damage

Sensei

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Sensei

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lBasket

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AndyG

Because some other guys are perverts

Sensei

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mrblaine

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mrblaine

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mrblaine

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Sensei

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lBasket

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mrblaine

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Sensei

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mrblaine

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Sensei

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mrblaine

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Sensei

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Rickyd

Nevermind!

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