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Discussion Starter #1
Really! In all my years of working on my vehicles, accumulated over a million plus miles, and I have NEVER broken a lug. I hand torque to spec. on top of it!

I was removing the lug nuts to rotate the tires and one got stuck. It cross threaded itself and then broke off. WTF? So now trying to het the rotor off the front, which is stuck, to replace the broken lug bolt.

Why is the parts guy not surprised? Are the metals used in Subaru parts sub standard? I have already had both rear hubs replaced due to bearing failure. Fits the substandard metals theory. And it is all not acceptable!:surprise:
 

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2008 OB Limited 2.5i, Portland OR USA
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I was removing the lug nuts to rotate the tires and one got stuck. It cross threaded itself and then broke off.
If it initially turned and then cross-threaded as it was coming off, it might be that it was damaged going on. Was there anyone else working on it last time this wheel was off? Are you the original owner? If it's only been you, what do the other studs on this wheel look like?
 

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Brucey
'17 3.6
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11,401 Posts
I've broken zero lug studs on 20+ vehicles. I've seen others break them but I never have personally. It's a pretty easy and cheap fix assuming you're doing it yourself.

I never have any luck with the bolt that screws in and pushes the hub out. I use a dead blow hammer to remove the rotor if I plan to re use it. Never had it leave any marks on the rotor.

How did a lug nut get cross threaded while taking the nut off the stud?
 

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'03 outback limited, '01 Outback Limited, '01 Legacy L wagon, '96 Legacy Brighton wagon
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How did a lug nut get cross threaded while taking the nut off the stud?



Not possible. It must have picked up some grit of some sort when being threaded on, causing small damage to the threads, and then galled the threads while being removed.
 

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2017 2.5i Premium Lapis Blue
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Not possible. It must have picked up some grit of some sort when being threaded on, causing small damage to the threads, and then galled the threads while being removed.
Either that or it was overtightened when installed and the threads were damaged/distorted at that point. Then when it was eventually removed the threads on the stud and the threads on the nut don't quite match up and it cross-threads. I had this happen recently when changing the spring bushings on my car trailer. I had one bolt that looked like it wasn't pulling up tight to the shackle and hit it a little longer with the impact rather than looking to see why it didn't pull in. It still didn't pull all the way in and the threads got damaged enough that when I then tried to take the nut back off it cross-threaded and then stripped right out so the nut just started spinning and wouldn't come off. I had to cut the nut just to get it off. Brand new bolt and nut, no dirt or grit involved, damaged needlessly by my own hurried work.
 

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Discussion Starter #6
Got it all done. Again, I hand tighten and torque all lugs. Hand remove. No air tools. No idea on why it cross threaded and broke. All other lug nuts look good. I do not know why.

Two 8mm screws into the rotor popped it off after treating with PB Blast.

Used a Lisle wheel lug tool to reseat new lugs. Part #22800. Worked great with an air wrench.
 

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2018 Subaru Outback Limited 3.6R Crystal White Pearl/black interior
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I have two lug bolts that will barely come off. It seems as though the threads have been compromised. We always loosen the lug nuts with a breaker bar and put them on by hand and then tighten them down with a torque wrench.

We have never had the problems, we are having with the 2018 Outback wheels, on any other vehicle we have owned. The lug bolts seem to be very soft metal or something is wrong with the threads.

I am contemplating replacing all 20 of the bolts to ensure that we are starting from known good, since we purchased he car used with 18K miles on it. It now has 25K. I am now investigating how tough of a job it will be to replace ALL the lug bolts.

Discount Tire broke one of the studs putting on my new tires today. I must say I was not surprised.
 

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I have two lug bolts that will barely come off. It seems as though the threads have been compromised. We always loosen the lug nuts with a breaker bar and put them on by hand and then tighten them down with a torque wrench.

We have never had the problems, we are having with the 2018 Outback wheels, on any other vehicle we have owned. The lug bolts seem to be very soft metal or something is wrong with the threads.

I am contemplating replacing all 20 of the bolts to ensure that we are starting from known good, since we purchased he car used with 18K miles on it. It now has 25K. I am now investigating how tough of a job it will be to replace ALL the lug bolts.

Discount Tire broke one of the studs putting on my new tires today. I must say I was not surprised.
Just thought I'd add my story. In September our 2017 Outback gets a flat. Using the stock lug wrench, I remove all but 1 of the lug nuts. The last one starts to come off, then binds. With no other option, I shear the bolt off - VERY easily and with a short lug wrench. I put the spare on and drive below 50mph to the nearest dealer about an hour away.

The dealer shear 2 more of the bolts that I just put on the spare. Granted I didn't have a torque wrench, but crikey, I'm not that strong and did not lean into tightening these. I was very careful putting them on - making sure that they were not cross threaded.

Fast forward a month and I take it to a tire place to have my snow tires put on. Two of the lug bolts/nuts that the dealer put on are bound and have to be replaced. The tire guy said that it is super common with Subarus.
 

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2015 3.6R Limited w/ES
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I've heard this is fairly common on Japanese makes in general. I've had 2 Subarus and never an issue, but I've also found lug torque from zero to gorilla after shops have had their way with them. I suspect these lug bolts are easily damaged by over-torqueing - last few times I've had my Outback's wheels off, I started noticing an increasing amount metal debris on the bolts (which I've since cleaned off). I'd imagine, if neglected, that could eventually cause some serious binding.
 

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Brucey
'17 3.6
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I've since invested in torque bars and use a half inch impact to tighten the lug nuts down.

Still no issues with the lug studs on the Gen 5 although some did go bad recently on the Suburban.
 

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'14 Subi OBW, '18 Subi Forester
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Fasteners don't magically cross-thread themselves. Somewhere during the life of the "system" the nut was overtightened causing plastic deformation (a stretching of the bolt without recovery to the original shape - permanent damage short of outright breakage). The thread pitch between nut and bolt no longer match, and galling (a form of cold welding due to damaged surfaces) results. You shouldn't hear a 'screech' of the tapered seat against the wheel with in-spec tightened fasteners.

We just purchased a CPO 2018 Forester. I had the Service Records pulled, and the owner had two broken studs replaced. When I got the vehicle home I jacked it up to check brakes and retorque lug nuts. Sure enough, most took extraordinary effort to remove, with a rather nasty sound for the first 1/8 turn. I suspect that I'll be replacing a lot of lugs in the next few months.

Torque sticks and plastic outer covered 19mm sockets are a good investment to go along with your impact tools. I use the 65 lb-ft stick in the cross pattern twice around, then finish with a click hand wrench to final spec.
 

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Fasteners don't magically cross-thread themselves. Somewhere during the life of the "system" the nut was overtightened causing plastic deformation (a stretching of the bolt without recovery to the original shape - permanent damage short of outright breakage). The thread pitch between nut and bolt no longer match, and galling (a form of cold welding due to damaged surfaces) results. You shouldn't hear a 'screech' of the tapered seat against the wheel with in-spec tightened fasteners.
^^^ What he said.

There are too many of us out there who are on their original lugs and wheel nuts who have never had an issue, for there to exist some yet-unknown and undocumented form of wearout, cross-threading, freezing, etc. The only argument someone might make here that fits the symptoms is operating a vehicle a long time in a winter road salt area without rotating the wheels or otherwise periodically loosening things up - and that would take a long time to develop, not a few thousand miles.

This is simple and plain abuse, and the cause is usually impact drivers. The smoking gun is that it's happening on multiple studs, not just one, which might suggest a scattered manufacturing defect.
 

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05 GT wagon, 09 Spec B, 18 3.6R Outback
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FWIW, I learned many years ago to use anti-seize compound on all threads on cars. When I first rotated the wheels on our 18' I coated the threads with the compound as I have done on all threads. I do have a 1/2" drive torque wrench too, for tightening. I use a 1/2" air impact gun to remove and 3/8" butter fly impact to run the lug nuts down.

I use the same process on all the vehicles, even did that on the Crew Cab Dually and the 40Ft enclosed trailer for the race car.

Anti-seize is your best friend.
 

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Fasteners don't magically cross-thread themselves. Somewhere during the life of the "system" the nut was overtightened causing plastic deformation (a stretching of the bolt without recovery to the original shape - permanent damage short of outright breakage). The thread pitch between nut and bolt no longer match, and galling (a form of cold welding due to damaged surfaces) results.
Amen. In particular, fasteners don't cross-thread themselves while being removed. Cross-threading occurs during the initial thread engagement, when the nut is being applied to the stud. Once the threads are damaged they may still appear to be OK for some time, but eventual failure is almost inevitable.
 
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Anti-seize is your best friend.
I agree, but you do have to reduce the tightening torque about 30% to keep from overstressing the studs and/or nuts, due to the lubricity of the anti-seize. Most manufacturers of top-quality anti-seize publish a "nut factor" (a.k.a. "K factor") specification to guide you in this torque adjustment. (The "nut factor" for clean, dry steel threads is typically about 0.20, while the published "nut factor" for the anti-seize I use is 0.12 - 0.14.)
 

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I hope folks are reporting these instances to NHTSA
 

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I have to strongly disagree to the use of anti-seize or any lubricant on a wheel stud.

Check your owners or service manual. This is one of the places where the wording is very specific: CLEAN / DRY THREADS.

Why? Lug nuts are used to apply a CLAMPING force of several hundred psi between the wheel and the hub. We have no direct way of measuring clamping force, so we instead measure rotational resistance (torque) of the nut against the treaded bolt, and of the tapered surface of the nut against the wheel. When you add a lube, you greatly reduce that rotational resistance, and thus accidently increase the clamping force. That increases the stretch on the lug, and puts undue 5 point compression on your brake disk. We can only guess at how much reduced torque is needed (is 30% the right number? I have no idea.) to compensate. Go too low and the nut might just back off (loosen) by itself. So we have a new danger introduced by messing with an established method.
 
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Through the years I have had no problems with large car lug studs. I have had problems with small cars. In my opinion, when tire stores rotate tires they use air guns to put the lug nuts on. whether they use torque sticks or not. The studs wear especially in the center. As general maintenance I take a flat edge and lay it across the stud. If I see an inward curve, the stud gets replaced. My 1994 Ford Escort had them replaced and my 2003 OB had them replaced once and the second time the "mechanic" lied to me stating that they did not need replacing so he did not replace them. That is after I inspected them and provided new studs. I contribute the wear to cheaper metal being used in the manufacturing process and the repeated use of the air guns. When I changed wheels, I used the star wrench, snugged the wheels down, then used the torque wrench. Re- torqued the wheels after about 50 miles. I have never replaced lug studs on any vehicle, when I have done my own work. I just do the work without air and a bit more carefully.
 

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I have to strongly disagree to the use of anti-seize or any lubricant on a wheel stud.

Check your owners or service manual. This is one of the places where the wording is very specific: CLEAN / DRY THREADS.

Why? Lug nuts are used to apply a CLAMPING force of several hundred psi between the wheel and the hub. We have no direct way of measuring clamping force, so we instead measure rotational resistance (torque) of the nut against the treaded bolt, and of the tapered surface of the nut against the wheel. When you add a lube, you greatly reduce that rotational resistance, and thus accidently increase the clamping force. That increases the stretch on the lug, and puts undue 5 point compression on your brake disk. We can only guess at how much reduced torque is needed (is 30% the right number? I have no idea.) to compensate. Go too low and the nut might just back off (loosen) by itself. So we have a new danger introduced by messing with an established method.

I understand the engineering. I also understand the real world. My 2005 GT wagon has 295,000 miles, I bought the car new, I have never had a issue using anti-seize on the lug studs. I torque all the lug nuts to 80-82ftlbs. As I do on most all lug nuts on all my cars since about 2000'. Even the race car which my son drove.

My 00' GT wagon was the only car I had any issue with lug studs, I used a thread Die to clean up the threads, I think some small stones got in the threads once.

I do most all the simple repairs, snow tire change over on my cars, so the wheels come off a few times a year. I'm 66y/o and have been working on mechanical things all my life. I even make sure I coat the ID of the hole on the brake rotor and Hub so less rust there when they need to come off next time.
 
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