The tire store touched all four wheels on my vehicle, and overtightened the lug nuts on the front wheels. It was a struggle to loosen them with a four-way wrench - I ended up using a 24" breaker bar on a few of them.
Is the damage done to the rotor immediately when the nuts are overtightened? They are at the proper torque specification now, but were in an over-torqued condition for 10 days.
Some cars can warp rotors while they tighten them if they use a circular pattern rather than a star pattern. You will feel that immediately.
How do you know they were overtightened? Did you check breakaway torque with a torque wrench? Have you torqued them in the past and noted breakaway torque. Or are you assuming they are over torqued simply because they were hard to loosen?
Yes, this. Whenever I remove and replace a wheel I use a torque wrench to tighten the lug nuts to the vehicle manufacturer’s specified torque value. A correctlly torqued nut would easily break free with a 4-way wrench or even a 1/2" ratchet wrench. When I have to get out the 24" breaker bar, the nuts have definitely been overtightened.
I don’t think the rotors will warp because the lug nuts are too tight. As long as they’re all tightened to the same torque in the correct pattern, I don’t see a reason for the rotors to warp. Could be wrong, maybe someone will disagree and explain.
I stopped going to the Toyota dealer I bought my 2012 Camry from because they so vastly over tightened them. I had to use a 4 and a half foot cheater bar over my breaker bar to get them loose, immediately after returning from the dealer.
I would say the torque to break them free was 300 ft lb or better. I know what 300 ft lb feels like because I used to change tires on my 18 wheeler and the torque on them was 300 ft lb.
The proper spec was only 85 lb. The other Toyota dealer did them perfectly when I went for state inspection. I keep a Snap-On 1/2" ratchet and a 2 ft cheater bar in the spare tire well in case I have to0 change a flat.
Never warped my rotors though. My rotors die from rust and pad transfer with all the road salt we use here.
I am guessing my issue was probably due to someone new to the business working on my vehicle because of the inconsistency of the lug nut torque on the four wheels. The rear wheels were torqued fine. The two fronts had three of the five lug nuts overtightened.
I will just make a habit of doing as bing noted and retorque after any service where the wheels had to be removed.
Last shop I worked at we purposefully designed the customer waiting room with almost no view of the shop and put yellow caution lines around the office and waiting room to demarcate where customers can and can’t go. From the waiting room you had a clear view of 2 of the 10 stalls.
The last thing a mechanic needs is someone looking over their shoulders while they work.
I’ve always loosened and hand-tightened the lug-nuts in rounds using a breaker bar/socket as soon as I get the car home, any time a shop has had their hands of the wheels. Takes very little time and mitigates against poor shop workmanship. Never had warped rotors, so no idea how long it takes. .
So how does overtorquing lug nuts warp rotors? The rotor is a flat surface. The hub is a flat surface. The area of the wheel that contacts the rotor is a flat surface. I’m not saying that I adamantly disagree that over tightening the lug nuts won’t cause the rotors to warp. I just don’t understand how since it’s just one flat surface against another.