lyonkster

So I had a new set of tires put on my GS430 last night, and as I was paying, the mechanic walks in and sheepishly hands me a broken stud, adding "Sorry, we overtorqued the nuts to 100 ft-lbs, and this one broke off - we'll pay to replace this one, but the others we backed off and retorqued to 85 ft-lbs".

I am now wondering if I have any grounds for asking them to replace all the studs, since they obviously overtorqued them. I am pretty certain they'll say that the one that broke must have been defective, and the others are fine, but I have my suspicions.

What would you do in this situation? Do you think there is any way I can get them to replace studs that are not broken?

Being an aerospace engineer (working with fasteners all day long, I might add ), it is a no brainer that even if the other studs have not broken, they may have yielded or cracked, but will I sound too much like an engineer trying to argue that point with them?

Leon

DaveGS4

iTrader: (2)

I'd try to get them to do it, if not I would formally send them a letter (with mail return receipt) letting them know that you have concerns about the other studs and should something happen to your car while driving in the future (wheel coming off on highway etc) that you would be forced to consider their actions contributing to the problem.

There was a similar question posed to the guys on 'Car Talk' last weekend I think, might be worth checking out their audio archives to listen to it.

rominl

iTrader: (4)

i agree, at least talk to them and make sure they agree that if down the road any of your studs broke, they will be responsible. since they overtq is and who knows what happens. not like they have x-ray to see if there are cracks

lyonkster

I had a closer look at the broken stud - it has all the signs of a classic ductile tensile failure - the body necked quite a bit in the last few threads, and also stretched.

It is amazing how much it deformed before actually breaking - the diameter went from .460" to .400", and the pitch went from .057" to .076" - that's a 50% stretch! Have a look at the attached picture. I am really surprised that the material on these studs is so ductile.

What concerns me even more, is that looking at the remaining studs on just one wheel, three look fine at a glance, but another one has clearly necked down to about .430". I guess that means I have a better case for them to replace all the studs, as this is not an issue of just "one defective stud" - they clearly were overtorqued significantly. But we'll see how the tire shop views it .

rominl

iTrader: (4)

wow damn, they sure they ONLY put on 100lb? that's really bad tq on the studs man

chuckb

I'd bet that they were much tighter than 100 ft lbs to do that. I'd guess more like 120, morons.

lyonkster

I agree. The sad thing is that this shop takes pride in using a torque wrench, instead of using the 500 ft-lb "spin it till it stalls" impact wrench approach. But, give a monkey a perfectly good torque wrench, and he'll still monkey it up. That's why I watched them the whole time, until I had to go pay, which is when they snapped it, grrrr. I watched how they "torqued" the lug nuts on other cars, no wonder they broke mine - the kid grabbed the torque wrench, and kind of jerked/snapped at it, instead of using the gentle and smooth motion that we all do (or should ).

Anyway, yes, I bet they put on more than 100 ft-lbs, and I am prepping for a fight. Good thing my sister is a lawyer, if it comes to that . Seriously, I will try to show them the evidence (one broken stud, another deformed) and see if the logic sinks in. If not, the gloves will start coming off .

chuckb

maybe you should get a to get it done at the Lexus dealer, and give them a bill.

lyonkster

Yip, I am planning to tell the repair shop that this is exactly what I will do if they do not see my side of things .

rominl

iTrader: (4)

not at all, at lexus dealership, i have YET to see them use tq wrench instead of impact gun. every time i see them work it's "droo drooo droo drooo drooo"

onihc

iTrader: (1)

which shop was this? my friend had one of his wheel stud snap after he brought it home from Costco tire dept. Costco totally made a mess of mounting tires. they put two weights on the same side to compensate for whatever amount of weight that was necessary. make sure your vehicle is safe to drive.

Tammy

You read about this all the time...
Using a local Discount Tire, I always specify my lugs be handled with a T-wrench only.. never an impact. This is loosen and tighten. They don't like it, but be insistant. It's your automobile afterall, you are the customer and you'll be watching. A suggestion may be to pay when the job is fully completed.
I also insist that I check their torque wrench setting prior to tightening. They are always wanting 85 Ft Lb and higher, while it should be 76 Ft Lb dry. But, their book says.... but it's wrong!

And an overtorqued nut will click the torque wrench fine without moving, giving a false reading. They wouldn't loosen then retighten if this occurs, at first. Now I have established a rapport with the business and they have my requirements preloaded in the computer. I provide the chrome wheel weights purchased at Lexus parts. And for no reason, leave the vehicle alone.

Lexus warped my rotors when I first purchased my RX300. The lugs loosened at 110 Ft lb. They said they used a "torque extension" on the impact gun, but they're not accurate. And Lexus had the opportunity to carve off half a millimeter of my four rotors to fix the vibration.. Haven't given an opportunity for a repeat performance.

lyonkster

This was America's Tire, the CA name for the nationwide Discount Tire chain. Their customer service has always been superb in the past, so this will be a good test case.

Unfortunately, they do nothing but tires, so they have to send me to another place to repair the studs, so this is getting complicated. Still, my plan is to tell the repair place that they need to either replace all the studs or tell me (in writing) that they inspected all the studs and found them to be free of defects. I can't see the latter happening, but you never know.

I'll keep you posted.

trent

Have all of the studs replaced! they were at fault for not having the correct torque settings.

lyonkster

Well, it ended up being somewhat anti-climactic. I had the mechanic remove all wheels and rotors, and we looked at every single stud. With the exception of the broken one and the other one that I noted was stretched, the others appeared fine. We ran a nut all the way down on each stud, and saw no thread deformation or stretch.

Given that the process of removing studs was not all that painless (they hammered them out, rather than pressing), I figured I'm better off walking away with just the two replaced studs.

I guess next time I'm at a tire shop, I'll insist on looking over the mechanic's shoulder as he spins wrenches - you know how much they love it when we do that .

Leon