Had new tires installed several months ago and I suspect the garage 'monkey' used the gorilla gun to set the wheel bolts into the aluminum of the wheels - screwing up the threads of one of the bolts.


I was removing the wheels and noticed one of the five bolts was actually not tight. I didn't think too much of it when I removed them as when I was putting the wheel back on and noticed that I was unable to tighten one of them. The threads on the bolt were not V-shaped, about half way on they were flattened to some degree.


Chasing the threads on the hub as well as the bolt did not seem to resolve the issue. I purchased a new bolt from the dealer but it would not tighten either so I'm at a loss what to try next. Suggestions?


Dale

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Dale

Sounds like the hub is stripped. I refuse to let a garage use a rattle gun to tighten lugs on my cars. I don't care if they use it to take it off, but to put it back on it better be a torque wrench or the tire tool in the trunk.

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Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

I strongly agree and will be ever the more diligent to tell them next time to NOT use the air gun when reinstalling wheels.


I suspect you are right about the hub. Would you know if I could tap new threads into it? The 'tap' I used to chase the threads was from a kit that Autozone 'rents' out and it was not a tap like I have ever seen or used in the past. Not nearly as 'aggressive' in looks nor in function (it seemed to me). IDK, maybe it is the 'new and improved' tap design of the 21st century!?!? It didn't seem to be doing much as I twisted it through the hole.


Dale

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Dale

Had the same problem after I had the tires balanced. One was stripped and damaging the bolt, making it unusable. Tapped it and all is fine now, it took me literally five minutes. Those alllu wheels are really soft.

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1979 Black on Black, 300CD (sold), 1990 Black 300SE, Silver 1989 Volvo 780, 1988 300CE (vanished by the hands of a girlfriend), 1992 300CE (Rescue).

Sounds like they stripped the threads out of the hub. Only choice is to Helicoil or Keysert it. If there is enough meat, the Keysert is the best repair. Helicoils don't do well with repeated bolt removal, like on a wheel. Keyserts do fine no matter how many times you remove and install the bolt. Get four or five of the inserts, as they are dirt cheap and in case one comes out later (although it shoudn't). The tool is a bit spendy, but required to do the job. Either way, it's cheaper than replacing the hub, especially if it's the rear on a wagon.

https://www.youtube.com/watch?v=UTdJUMIcrPI

The damage may have been from over torquing with the impact gun, or could have been from galling coming out. Almost NOBODY ever anti-seizes wheel bolts. A friend runs a tire store and is careful to anti-seize EVERY lug bolt and nut he replaces for exactly this reason. A can of nickel anti-seize is just a few bucks and is worth it's weight in gold for preventing galling like this. Also put it on spark plug threads for the same reason. Thermostat housing bolts, etc... anything that goes in aluminum or acts like it might want to gall coming off or going on. Got hooked on using it at the pump shop taking apart corroded stuff and then at the hydraulic shop for large diameter fine threads. Sure makes life easier.

Thanks for the recommendation on the Keyserts. I'm unfamiliar with such a solution but now I know! Are these available alacarte or would I have to purchase a bulk quantity? If you have a good source and a link I'd surely appreciate it.

Regarding anti-seize: it seems that I ran across this at some point. I've heard that it will interfere with torque value. Any knowledge on that?

Dale

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Dale

I apply antiseize to wheel bolt threads. Haven’t had a bolt loosen or wheel fall off yet (touch wood).

Sixto
98 E320s sedan and wagon
02 C320 wagon

FSM torque values for wheel bolts are dry values for clean, rust-free threads. If you lubricate the bolt and use the same torque value, you will be applying more clamping force. That risks damage to rims, bolts and threads. The bolts are probably 25% below their load limit at specified torque, so you may have enough reserve strength to get away with it. But it's a still a risk you need to think about. If you know the thread size, you may be able to find a table of appropriate wet torque values by internet search.

I have super glued lug bolts that were stripped,till I could get new bolt.

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1999 w140, quit voting to old, and to old to fight, a god damned veteran

Threads wear out even when installed / removed by hand.

The factory says to install dry, this leads to friction and galling. ( Galling occurs when 2 of the same metal types rub against each other. In a mixed metal situation, softer metal will wear away, but in a similar metal situation, both parts ball up. ) I use oil on the threads but not on the taper / ball seat.

Another issue is rust. The lug bolts extend through the hub, if the exposed threads rust they will damage threads as they are removed. Add in grit from brake pads and you have an abrasive mix.

Failed lug bolts / studs are not always the fault of the last person that touched the car as bolt wear is a progressive failure. It is possible to properly install a bolt by hand only to have it snap off / cause damage when properly removed.

If this is a front hub, I'd just replace it. If rear I'd replace hub only if the bearing is due for replacement. Cleaning with a tap won't help as this removes metal that already isn't there. I'd use a Helicoil if there isn't much metal around the hole or a Time sert if there is room. If yo use a Helicoil, you will need to be careful when installing the bolt as if the coil end lifts, things will jam.

I just ordered them from McMaster-Carr, you can buy as few or as many as you like. I'd say you are looking at $25-40 to fix that, yourself. You will need to buy a tap and drill for the next size up to install, as well.

"Regarding anti-seize: it seems that I ran across this at some point. I've heard that it will interfere with torque value. Any knowledge on that?"

Common sense says a lug with proper anti-seize on it is going to torque a lot more accurately than a dry bolt in a dry hole that galls before it reaches full grip. If you ahev ever had a stainless nut gall on a stainless bolt while running it down with your fingers, this will be very clear. I have been using anti-seize on all my wheel studs adn bolts for several years now and have never had one loosen up or fall off... or gall and strip.

"FSM torque values for wheel bolts are dry values for clean, rust-free threads. If you lubricate the bolt and use the same torque value, you will be applying more clamping force. That risks damage to rims, bolts and threads. The bolts are probably 25% below their load limit at specified torque, so you may have enough reserve strength to get away with it. But it's a still a risk you need to think about. If you know the thread size, you may be able to find a table of appropriate wet torque values by internet search."

The amount of extra force applied with the anti-seize is going to be negligible, percentage wise, if in doubt, torque to the lower value of spec and it would not exceed the upper limit by more than single digits percentage in the worst case. The torque wrench could be that far off unless you have it calibrated yearly. A lot less likely to damage anything than galling, as is the case with the original issue here.

And no, don't anti-seize the tapered seat of the wheel or lug.

Just an FYI to tuck away in your tool cabinet. From the Anti Seize Technology web page.


https://www.antiseize.com/PDFs/torque_specifications.pdf

Attached Files

torque_specifications.pdf (86.2 KB, 285 views)

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Gute Fahrt

That is an extremely dangerous and oversimplistic conclusion. It is absolutely not common sense as you claim. Lubing threads can increase the torque readings by much more than a few percentage points. Please share where you got this information from because it's known that it can be much higher than that. Tool makers are well aware of this. It's why an impact wrench with a spec of 500 lb/ft may not be able to break a lug nut torqued to 100 lb/ft.

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#dontdealwithkahlil

If the hole in the hub is stripped then you can't fix it by tapping it. If it was me I would just get another hub from a wrecking yard. Second idea would be take the hub off and take it to a machine shop for thread repair.

As far as anti-seize and torque values, the most important point is never get any anti-seize under the head of the fastener. Make sure it is just on the threads, and I tend to use it sparingly, just enough but not too much.

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1998 C230 330,000 miles (currently dead of second failed EIS, yours will fail too, turning you into the dealer's personal human cash machine)
1988 F150 144,000 miles (leaks all the colors of the rainbow)
Previous stars: 1981 Brava 210,000 miles, 1978 128 150,000 miles, 1977 B200 Van 175,000 miles, 1972 Vega (great, if rusty, car), 1972 Celica, 1986.5 Supra

Lots of bad answers here. The clamping effect of a bolt is determined by elastic deformation. The more the bolt stretches, the tighter it holds. If the bolt is dry, the threads and head generate more friction than if they are oiled, which should be one thing that’s obvious to everyone. As a result, it takes more torque to achieve a specified strain when dry than it would if the bolts were slippery wet. So if you oil the bolt, tightening torque must be reduced or you can exceed the point of plastic deformation, which is where threads strip and bolt heads snap. Once you oil the bolt, the manufacturer’s spec is out the window, so you’re on your own. The only thing that’s saving some of you is that Mercedes assumes clueless mechanics and designed the system with some reserve.