Reciprocal

My beautiful ZR1 has the dreaded 75 mph steering vibration. Made appt with the dealer service, diagnosis was worn tires, recommended replace tires, spin balance, front end alignment. After new tires and service, picked up car, better but underlying vibration still there. Took technician for demo drive, he confirmed vibration to the service advisor who contacted GM next day. Service advisor called back next day, said GM field rep recommended road force balance which dealer doesn't do nor could they arrange with 3rd party. Handed problem back to me, unresolved. They steered clear of any discussion of rotors.

JMBLOWNWS6

Its the rotors. Roadforce isnt going to fix that.

nightflyer

I had the same problem, I went to my dealer, told him what was going on, he then called his district manager and told him what I had told him, he...the district mgr...said he was aware of the problem, order him two new front rotors and install them...no questions asked, no BS, four days later I received a call that my rotors were in and the next day they were installed...problem solved!

mirage2991

So nobody can do a road force balance in or near your town?

Call customer service and have them open a claim.

Reciprocal

I'm taking it to another Chevrolet dealer in the morning, that has the gsp9700. I also found a company Denver Balancing that can balance the rotors, with precision. He said he could remove material, or not molest them and give me the weight at 19 inches for indexing. He's been in business for 28 years, can do rotors no problem, armatures whatever, from 1 lb to 1000. Said he can add clay to bring it into balance, then he weighs the clay. Sounds worth a try. I think you've been thru a similar process. Of course I'd rather have new rotors, but GM nor the dealer Purifoy have been helpful.

Gary '09 C6

you do know that the CC rotors have a minimum weight stamped on them, correct ?

It's my understanding that the rotors need to be replaced if they weigh less than that minimum.
If you haven't tracked the car steadily (and no other damage, of course) yours should be OK...

Reciprocal

Well, yes I was aware they had to be weighed, not measured, but I had forgotten that the min weight was marked on the rotor, thanks for reminder!

And I had wondered if Purifoy had weighed them when they verbally told me the rotors checked good, so I just looked at the certified multi-point inspection report attached to the invoice, and sure enough, they wrote 10mm front, 8mm rear, (good), which is just confirmation they don't even use the right procedures for checking them. What's really sad about it, they are the largest corvette dealer across several states, their service bay had 9 new C7's crammed in there getting prepped, all sold, they still have one zr1 left, they have a dedicated corvette showroom floor, and all this in a sleepy rural town 30 miles north of Denver called Ft. Lupton. Nice people, all of them, but I still fault them because I think they should do more than hawk tires, alignments and spin balances to people with ZR1's that have well documented cases of steering vibrations which is what I brought it in for, not just new treads.

Reciprocal

I will have Denver Balancing weigh the rotors.

K B Vettin

Just my opinion but I would press harder for the new rotors and simply not expect a no for an answer. It seems like a lot of members have asked and heard no but pressed the service manager harder and harder and got them. Just my .02

Reciprocal

Yes you are correct, press harder I will. That said, if they said I needed tires, I had to buy them, if they said I needed alignment check, I had to pay for it, if they said i needed road force, I had to pay for it, I can't really push for my own preferred solution (rotors) until I've exhausted what they say could be the problem, until we get to the point where rotors are the only thing left to try, or they try to say it's normal characteristic. The goal is getting rid of the vibration, not getting free rotors. But if it all fails and still short of new rotors, I'll hire an attorney.

Reciprocal

One rub is the $60 I already paid to them for a spin balance, when I queried "no road force machine?" they stated at that time, "oh no,..we don't believe in them..." then gm field rep subsequently tells them I need one.

I can speculate only at this point, but Denver Balancing's findings could play into this as well if they determine the rotors are 1-1.5 oz off, which I think would be quite enough and probably more than they would be expecting from iron rotors, by a good margin. Need the road force result as well.

05dsom

There is a whole sticky (24 pages) on this in case you want to see what others have tried and been successful or failed with...

http://forums.corvetteforum.com/c6-c...on-issues.html

Reciprocal

I think the service ticket measurement was pad thickness, should backtrack on that one. Lug nuts were on over 100 ft/lbs, bent handle of my torque wrench, need to buy 1/2 inch extended handle to break loose caliper bolts.

jft69z

GM service bulletins specifically say to RFB the tires for this condition on the Corvette. Single digit numbers are the target, with 10 being the upper limit if I recall.

We spun all of the rotors for my car (6 total) and some still vibrated on the car with 1/2 -3/4 ounce of imbalance.

You mentioned something about Denver Balancing removing material from the rotors earlier? Don't think that's possible with the CC rotors on our cars, be careful what they try to do to them.

Is your car still under warranty? If so, all of the procedures mentioned should be done for free I think.... My tires, RFB, and rotors were all done free of charge under warranty.

Joe T

Reciprocal

Here's the latest: Ed Bozarth Chevrolet road force balanced the front wheels with the new front tires just installed by Purifoy. "ONE TIRE OUT OF ROUND CAN NOT FIX."

Specifically, the good one was near perfect, 3 to 13 pounds of road force variance depending on who I talked to, the service advisor or the tech, but the other tire was visibly out of round as soon as they spun it, even before applying load. He tried indexing it to the rim, but it made no difference as the rims are true, no runout. He balanced it anyway, said the road force variance was 40 lbs. The service advisor said Purifoy should replace that tire under the manufacturers warranty.

While they had my tires I pulled the rotors and will have them weighed and checked for balance. I will not add or remove weight to the rotor itself, but will index it to a weight added to the wheel rim. Of course if it's really far out of balance, I'll try for a replacement rotor for manufacturer's defect, but right now, there's a known problem with the new tire. The rotors and pads otherwise look in fine condition.

Some reason for optimism now, I can see this working it's way toward a solution.

Gary '09 C6

from my post in the "sticky thread" at the top of the ZR1 sub-forum, about this issue.


http://forums.corvetteforum.com/1581922671-post362.html

seamus2154

I went through this same issue for months. They are well aware its the rotors. They try everything not to replace them. Some have even gotten them balanced and then when you take your rims off for any reason it starts all over because they compensate for the out of balance rotor by balancing your tires and rims and indexing them to the rotor. Problem is it is indexed to that lug nut w/ those tires. They know it's the rotors. I finally got all four done and no indexing or road force balancing needed. It was the rotors!!!!!

K B Vettin

I had a 2010 and it had the vibration but for many other reasons I got a 2013 and these rotors have weights that the 2010 didn't have. That proves that gm admits there was a problem that needed to be fixed. I am on a road trip through tx now and I was driving 85 on the 10 and 20 for long periods of time with no vibration at all. I'll take some pics of the weights I'm talking about and post them. You should tell the service advisor that they need to add the weights that were used to fix the vibration in the 12's and 13's or give you new rotors. There is absolutely no disputing that the weights were added to fix the vibration. Also since you said the dealership had a 13 zr1 on the lot you can see the weights on the front rotors in person and show them to the service advisor

jft69z

Hi Kristopher,

I don't think the weights are available thru GM, they come from Brembo with them on there. My '13 didn't have any weights on the rotors, only 1 of the replacement rotors did, and it was a vibrator on the car (figures...). In fact, I think that was one of the rotors that was out of round too.

There are pictures in one of the other threads that show the weights.

http://forums.corvetteforum.com/1582225149-post1.html

http://forums.corvetteforum.com/1582233863-post6.html

I drove across Texas once when I was in the Air Force, seemed like it was never going to end. Would have been a lot more fun in a ZR1 .

Joe T.

DebRedZR1

New Rotors. If they won't go that route let me know. This should be a non issue at Stealerships but unfortunately some dont get the meaning of customer service. Good luck