cyi1

Ever since day 1, I had a slight vibration in the brake pedal and steering wheel when applying about 15-20% brake pressure to come decelerate from moderate speeds. I made the dealership aware of this for when I go in for my 500 mile oil change.

The tech drove my car for 45 minutes and said he did feel a slight vibration and it didn't seem like an issue but to let them know if it worsened.

It feels like it has worsened when braking between 50-80MPH. It's the worst during those speeds and goes away before hitting 30MPH but it does feel like warped rotors would on any other car except it doesn't do it under very hard braking.

If I do hard brake pedal pressure around 70MPH like I'm burnishing the pad, the car brakes really hard with no vibration issues.

I took it in again to Rick Hendrick Buford (I won't ever go back there) and the tech agreed that it worsened, but on the call I got from the service advisor, he stated they won't do anything for me because the Katech titanium lug nuts must have been torqued improperly and warped the rotors.

It was frustrating when they were aware of the vibration from the first drive, but now the lugs (that were torqued to 100 ft lbs in a star pattern which is basic knowledge) are the case of the issue so they told me to pay for replacement front rotors.

I picked up my car and left. I had heard bad things about the dealership but friends told me they were a lot better than Rick Hendrick in Duluth so I took the car there.

I'm 100% certain it isn't the lugs because I watched as they were torqued to 100 ft lbs, but I asked Jason at Katech anyways and he also said it's not even possible for the lugs to have caused it.
Now I'm not sure how to proceed ------

1. Should I try doing the complete burnishing procedure for the pads to see if it gets better? Is there a requirement for outside temp? I can do it early in the morning but it's been cold (around 40 degrees in the morning)

2. Should I put the stock lug nuts on and take it to another dealership? (I'm sure it's already in the computer blaming the lugs because it was printed on invoice at pickup)

I've looked all over and saw all the threads of the ZR1 carbon ceramic vibrations that could have been from the rotor being improperly balanced from Brembo. The video I saw showed a ZR1 user having steering wheel vibration while cruising at 70mph without applying brake pressure so I'm not sure if it's the same issue here.

Everything I read about carbon ceramic brakes lasting the life of the car if I only drive on the street was such a positive reason to get them, but now a part of me wishes I hadn't.

Bob U

Find a new/different Dealer, lug nuts have nothing to do with it!

cyi1

I am going to let Jim Ellis know on my next oil change.

Should I put the stock lugs back on?

They have it documented that I have aftermarket lugs. Should I just take it in with the Katech lugs and argue that it can't be because of the lugs?

RichieRichZ06

I would be more inclined to think it was corrosion between the rotor and wheel and it's exaggerated under certain braking events. As others have stated, it's impossible for the lug nuts to cause it and the dealer you went to is simply an idiot.

I would not rule out an issue with the rotor, but the only way to be sure is to check lateral run out on them. Many times you can reduce or eliminate the amount of run out by clocking the rotor differently on the wheel studs. This was a common issue with the ZR1/Z07 cars in 2009-2012, but I have only seen 1 C7 model with excessive run out on the rotors that was not corrected by cleaning the mating surfaces or clocking the rotor.

RICH

cyi1

Thank you. I'm going to bring this up when speaking to my next service advisor.

noel48

I have same issue with base brakes.Dealer said it was the torque converter and replaced it.Still have the vibration.

thebishman

You may have an issue with inappropriate deposition of pad material on the CCMs. I would perform a complete ‘burnishing’ before you do anything else.

There was an issue with the CCMs on the C6’s where the rotors themselves weren’t balanced; GM replaced those iirc, but it hasn’t been an issue with the C7 that I can remember.

Bish

cyi1

My car is a M7

I'll definitely do a full burnishing and see how they are afterwards. Does it matter what outside temperatures are while performing the procedure? I would have to do it very early in the morning to avoid other cars which means it would be about 35-40 degrees outside.

Steve Snake Driver

How is it possible to warp a CCM rotor? I would think they could crack or shatter but never warp.

Maybe try a runout gauge on the rotors to see if they are dimensionally correct.

thebishman

Exactly; you can’t warp one. To even suggest so shows that the ‘tech’ needs a remedial course in brakes!

BELVIN20

Just had the same thought, do not think it is possible to warp a CCM rotor, all I have ever seen is that they will wear out when tracking, & they will break & are expensive.

cyi1

LOL that's why I picked up my car and quietly left without raging. I will NEVER go back there again if that's what their one and only Corvette tech had to say about the issue.

I just got off of the phone with a service advisor at Jim Ellis Chevrolet and I was completely honest and up front about what Rick Hendrick had to say about my lug nuts. I told him it's BS and if he wants to help me figure out what's wrong with the brakes then I will bring it in. If he wants to blame lug nuts for warping carbon ceramic rotors then I will go somewhere else and not waste both of our time. He said he will speak to the corvette tech and call me back by tomorrow.

3 Z06ZR1

Check your front disc's for any pieces broken off by rotating them slow and look them over. If you find a piece missing that is your issue.

cyi1

Got my balance done a couple weeks ago and I checked them thoroughly while wheels were off. No issues I could see.

RichieRichZ06

I've had several that got chipped by rocks on the wheels and other impacts. I've never had a vibration from them, even with small chunks missing.

These rotors are a lot more robust than people think and you don't have to treat them like fine china plates. I never use the foam protectors and I've had a lot of rocks scrape and scratch them up. I still road race with them and don't even think twice.

hcvone

All the lug nuts are the same correct? What I am trying to say you don't have any wheel locks on correct, the lugs are all the same? I say this because we have had some balancing issues thru the years when a customer is using 4 like lugs and one heavy wheel lock, and at certain speeds there was a vibration, most speeds it was perfect, we kept balancing looking for the problem, why it took long to find is the customer brought us the wheels only and he installed them so we had no idea of the wheel lock, until he showed up with the car

cyi1

All lugs are the same. 20 Katech titanium lugs.

Gonzo

Interested to hear the solution .

cyi1

Found the dealership invoice.

Incorrect lug nut torque

hcvone

You just can't make this stuff up.