2016 Audi A6 - Rotor warp from bolts?

I took a 300 mile trip on Audi A6. The car used lug bolts. When I arrived at my destination I noticed I was missing a lug bolt and two of them were hand tightened. I immediately bought a replacement and tightened the other. After 6 months my car started shaking when I would brake. I balanced wheels, aligned front end and also turned the rotors. 6 months later same issue again. Took to Audi dealership and I’m paying $1500 for new brakes because they are warped. That was the issue the whole time. Could it be possible that my rotors were initially warped from driving 300 miles without a lug bolt and 2 hand tightened ones? Or just wear and tear? Or some other reason?

What are you getting for $1500? Just rotors and pads? Calipers?

Anytime a wheel is installed and isn’t torqued up properly, it can put stress on the rotor. Also, if the lug nuts are tightened unevenly, they can lead to the brake discs warping.
I would also wonder why they were loose. check to make sure the lug threads are not damaged. also check to see if the lug holes in the rim is not oval.

2 Likes

True. But it’s also entirely possible the prior lug-bolt issues are not related. In my experience a single missing lug bolt w/ two still at least hand tight, that wouldn’t cause major symptoms. With two missing and 3 quite loose, yeah, you’d likely get major symptoms then. I find lug bolts in the gutter along side the road quite often, found one yesterday in fact. “Hey, this is from Germany” … lol …

Yes. it is very possible to warp rotors by improperly tightened lug nuts.

1 Like

How many miles were on the rotors when you turned them the first time?

I agree with weekend-warrior that you want to check for thread damage caused by the loose bolts. I hope you’ve been checking the bolts for tightness frequently to be safe.

I want to know what you meant by “turned the rotors”

if a professional mechanic were to say that, it would mean he machined the brake rotors

Is that the case?

If you do a poor job . . . I’m not getting into the details at this time . . . it could make the rotors very likely to warp in a short time

1 Like

Brake rotors are not cantilevered so uneven torque of lug nuts/bolts is not going to warp them. What will cause them to warp is if the castings are not heat treated before machining or not properly cooled after casting.

If you had the rotors replaced before all this started, you may have gotten aftermarket rotors that do not meet Audi’s standards. If you had the pads replaced with non OEM pads, you may have had a resin transfer issue and not warped rotors. Not all aftermarket pads are bad, some are better than OEM, but you do need to know which are the good ones and which are not.