Snapped wheel studs, bad technique to blame?

[sciphi]

I recently had to replace two snapped wheel studs on my Cruze, one on the driver's side front wheel, one on the passenger side rear wheel. I was rotating the tires, and the snapped studs occurred when torquing the lug nuts down to the recommended 100 ft/lbs of torque with my torque wrench. Prior to snapping them, I had hand-started all the lugs, gunned them down with my cordless impact, and gone around the car to tighten the lugs to 80 ft/lbs. I was using a deep-well socket and a 4" extension, and tightening slowly until I heard the wrench click. The wrench is a 1.5 year old Craftsman 1/2" clicker torque wrench. The snapped ones never clicked, they simply twisted right off. The other studs on the affected wheels felt sort of "stretchy" as they were being tightened, but they did click at 100 ft/lbs.

In the name of safety I replaced all the studs on the affected wheels since it was $20 for 10 studs, the car was up on stands, and the front was a nightmare I didn't want to repeat. The new studs didn't have that same "stretchy" feel the old ones did. I left the torque at 95 ft/lbs to err on the side of not snapping a stud I'd just replaced.

I've tried to recollect the events as best I could. So, was it my technique at fault?

 

[user52165]

Under warranty? Tough case to prove but Government Motors (that's you and me and BO) should know about this.

Check with another known good torque wrench.

 

[webfors]

Had the same issue with my 2010 Corolla @ 90 ft-lbs. However, they are spec'd for no more than 80.

The torque wrench just kept on turning with no 'click'. Eventually the lug nut just tore off. It was soo easy though, like there was no backpressure.

Now I make sure I go **really** slow, with small short action (think small range of motion).

 

[Donald]

You can check your torque wrench with a beam torque wrench by doing something to have two sockets stuck together and then torque away.

 

[NHGUY]

Remember the Cruze had the steering wheel come off and led to a recall,maybe the road wheels are now doing the same?

 

[2009Edge]

How old is the Cruze?
Have you had the wheels off before?
Did you do the work?

The wheels may have been over torqued by someone in the past, you just found it before it became a real issue on the road. Lucky you.

Personally I WILL NOT let anyone rotate my tires. I do it myself and use my own torque wrench. If per chance I have to have a tire repaired I recheck the torque in their parking lot. Trust the one you see in the mirror.

 

[Carbon]

Did you put anti-seize or other lube on the threads? If so, you would want to use less torque.

 

[Texan4Life]

I assume the threads were dry. In that case you did fine, and I would blame it on low quality studs.

Even if he lubed the threads, I would expect it to strip the threads, not twist the stud off.

my .02

 

[sciphi]

I've been the one doing the work on this car, except when it needed its state inspection. I've always used that Craftsman torque wrench on the wheels, which have been rotated, swapped to winter wheels, or otherwise off the car approximately 5-6 times before this had happened. I always used a torque wrench set to 100 ft/lbs after hand-threading and tightening with a cordless impact. No anti-seize or other lubricant was used on the threads.

I decided not to ask for warranty consideration since I was the guy who broke the studs. I broke 'em, I'll replace 'em on my own dime. And, I feel I do a better job on my own car than asking for a tech to cut corners on the 0.3 hours it pays to change a broken stud.

And, let's please not get any more "Gub'mint Motors" political hoopla. I drive a Chevrolet. It had an issue I'd like help with, not a political lecture. Take the politics out of my thread, please.

 

[dparm]

Even if that torque wrench was off by 20%, I find it hard to believe there's that small of a margin and they broke. I think it was just old age, or a bad stud.

 

[antiqueshell]

Originally Posted By: sciphi


And, let's please not get any more "Gub'mint Motors" political hoopla. I drive a Chevrolet. It had an issue I'd like help with, not a political lecture. Take the politics out of my thread, please.


I agree with this because many other manufacturers received loans that were similar like Ford did.

If I understand correctly the studs failed when you were removing them and the prior to this they were worked on by a dealer?

Sounds like you need to go back to that dealer and let them know that somebody damaged the studs when reinstalling them. Sloppy or careless work!

 

[Rand]

how tight with the impact its 700ft-lb?

when you tighten with the torque wrench it moves right?

its not just click and done?

I usually tighten to 60# or so with an impact and torque stick

then final tighten with about 80# with the torque wrench.. it moves about 90degrees.

 

[johnachak]

700 Ft lbs.? A typo I hope.

 

[sciphi]

Originally Posted By: antiqueshell
Originally Posted By: sciphi


And, let's please not get any more "Gub'mint Motors" political hoopla. I drive a Chevrolet. It had an issue I'd like help with, not a political lecture. Take the politics out of my thread, please.


I agree with this because many other manufacturers received loans that were similar like Ford did.

If I understand correctly the studs failed when you were removing them and the prior to this they were worked on by a dealer?

Sounds like you need to go back to that dealer and let them know that somebody damaged the studs when reinstalling them. Sloppy or careless work!


It was me who snapped them. I was the one removing them before that, not a dealer. The inspection station removed a single wheel, and that wheel wasn't affected.

My cordless impact tightens the lug nuts to maybe 60 ft/lbs. I can move them easily with a torque wrench set to 80 ft/lbs after tightening them with the impact.

It's sounding like it was bad studs instead of improper technique.

 

[doitmyself]

Originally Posted By: sciphi
Prior to snapping them, I had hand-started all the lugs, gunned them down with my cordless impact, and gone around the car to tighten the lugs to 80 ft/lbs. I was using a deep-well socket and a 4" extension, and tightening slowly until I heard the wrench click.


This is a bit confusing. Did you snug them up with the impact, then torque wrench them to 80 ft. lbs., then again to 100 ft. lbs.? Or, are you saying you somehow used your impact to get them to 80 ft. lbs. first. EDIT...you cleared this up above!

As Rand suggested, torque is measured and set on a MOVING nut (proper procedure).

It's best (IMO) to do a minimum of two torque wrench operations....ie., 80 lbs., then 100 lbs.

What else could it be, except:

Bad wrench (intermittent)?
Previously damaged bolts (factory?)
Poorly mfg. bolts.
Poor technique....your impact is over tightening and causing damage.

A deep well socket AND 4 inch extension could be inducing some off axis error if you are not careful (not length error).

Best of luck. Good that you replaced all bolts.

Final edit....your post above answers a lot. It does seem that the studs were defective.....but how or why?

 

[Falken]

If you have a click type torque wrench that is long (for example 50-250 ft lbs) it is very hard to tell how much torque you are putting on the studs, so it is very hard to be careful if you have no confidence in the torque wrench when the wrench is that long (a lot of leverage).

Generally, a torque wrench that fails to click properly is out of calibration. These are worse than using no torque wrench at all, as you will overstretch the bolt before you get nervous and stop. Especially a long torque wrench, as you can damage a wheel stud very quickly.

There is a very good chance an impact stretched the studs in the past, and now they just shear off like fatigued aluminum.

What I have noticed is no matter how gentle you are with an impact gun, you can exceed 100 ft. lbs. very easily, where you have to back them off with a breaker bar a touch before using the torque wrench to get some angle of rotation before the torque wrench clicks.

If you use an impact, then use a torque wrench and it clicks without the bolt turning at all, it is over tight and needs to be backed off and re-torqued.

What I have started to do is torque by feel with a reasonably sized ratcheting breaker bar, and get used to being about 90 degrees shy of the proper torque, then finishing it off with an actual torque wrench.

This way, if the torque wrench is out of calibration and doesn't click, I know to stop turning it at a reasonable point and double check that my torque wrench isn't out of calibration.

So then, I have a smaller torque wrench that goes up to 75 ft-lbs, and I back off a wheel nut and torque it to 50 ft-lbs.

Then I set my longer torque wrench that I doubt to 50 ft-lbs, and if it keeps turning past I know that it is out of calibration.

I am starting to believe that a beam-style torque wrench is the way to go. You don't have to spool it down before storage even.

If I ever get a beam torque wrench, I'll use a ratcheting breaker to snug, then use the beam to aim for 90 ft-lbs, then nail it with the clicker for the final 100 ft-lbs. (for example).

Edit: Forgot to mention, if you have a really long 50-250 ft. Lbs torque wrench that fails to click, it would lead you to think that the studs are to blame as they would just break off that easily with that much leverage. It would feel like tearing through something made out of aluminum or soft lead. Go down in range to something shorter that would give you more "feel" to avoid breaking studs.

 

[sciphi]

Originally Posted By: Falken
If you have a click type torque wrench that is long (for example 50-250 ft lbs) it is very hard to tell how much torque you are putting on the studs, so it is very hard to be careful if you have no confidence in the torque wrench when the wrench is that long (a lot of leverage).


Falken, mine's a 24" 20-120 ft/lb torque wrench. How long is the wrench you're discussing?

I also have to hand-tighten the lug nuts with it even when I impact them on because my cordless impact can't tighten lug nuts anywhere near tight enough. It's great for removing them, not so much for tightening them. IIRC it'll do a lug nut to about 60-70 ft/lbs. They always need to be hand-tightened to the proper torque specification.

I skipped the 4" extension and used only the deep-well socket on the torque wrench this last time. That gave me a better feel for where the lug nut was, since the extension wasn't absorbing any torque. I'll skip the extension from now on unless it's really needed.

It's possible it was a marginal stud, and using the extension was an error on my part. The twain met, and off it snapped.

 

[CapriRacer]

One thing not yet mentioned.

When tightening a nut, you want to support BOTH ends of the wrench. That way you are only applying torque and not adding bending stress.

Remember the old style lug wrenches - the 4 bar kind? Those were easy to apply torque only because you used the unused bars to turn. Think of using the same technique even though the torque wrench is off center.

Upward force on one end - equal downward force on the other.

 

[Kestas]

I agree if you're using an extension for the socket. Then I support the head of the wrench with my other hand. Otherwise, every torque wrench I've seen is conventional and not the 4-bar cross design.

 

[Rand]

so when are you replacing the other 10 studs?

if half were that bad I think I'd want all new quality ones.