Has anyone needed to replace the rotors yet? Lots of questions.
 

I have the vibrating steering wheel problem many have had. I have had my wheels road force balanced but the vibration is still there. I brought the car to the dealer where it was bought (a good forum dealer with a dedicated corvette tech). He set out to address the problem as others have done, with balancing, indexing, etc. I am on my second set of pads but after only 2 track days and 9 sessions (most on PTM 3) he said the thickness on the pads is 3 mm in the front, 4 in the rear, and that they will need to be replaced if I am to continue to track the car. The last set of pads lasted 4 track days and 18 sessions.

Part of the process to get rid of the vibration is to weigh the rotors and see if they are balanced, as well as check the wear by thickness. I am in a time crunch as I am trying to go to Road America this weekend. I was told that to get accurate measurements the rubber/pad material, etc would need to be cleaned off the rotors. If the time was spent to do that and then it was decided to order rotors they would not come in time, so new rotors should be ordered as I will likely need them once I am in a third set of pads anyway (apparently collected wisdom re: carbon ceramic brakes but I have not heard this one).

My concerns are:

1. Shouldn't these rotors last more than 6 track days and 27 sessions? My only consolation with this is that if my vibration was from rotors that were not originally validated at Brembo as being true and if the new ones are true, the vibration will be gone but at a serious price.

2. Should the rears be replaced? The rear pads have much more wear in general than on my Z06 likely because of PTM. I wonder if that is true of the rotors. On my Z06, the rear rotors lasted a long, long time.

3. As the rotors do wear, should the second or third set of pads have a shorter life span because of decreased heat dissipation?

4. I was told that to clean the rotors and weigh them etc it was a time consuming process and there would be a fee. On one hand I am not surprised given the complaints re: maintenance costs on other high end cars with CC brakes. On the other hand, if this was being done to check if the rotor was true to check for a reason for vibration or if this was being done to check the wear to see if I needed to order new rotors, you would think that the time spent on this process would either be a warranty or courtesy.

I still am happy in general with the CC brakes that can handle street and track use. On the other hand, I was at the track recently with 3 guys who drive GT3RSs and the day they get the car they take off the CC brakes, replace them with steel and either sell them or put them back on when they sell the car. I am beginning to see the point the hard way.

All thoughts appreciated, esp from the ZR1 track regulars who usually chime in.

IMHO, once you track your car all bets are off

If there is any material embedded in the rotor, it's damaged. The rotors should be as smooth as a baby's backside, even after lots of use. Nothing should be sticking to them at all. Whomever told you this is full of it.

"Collective wisdom" doesn't apply here at all. And your Chevy dealer doesn't know crap, unfortunately, because I can guarantee they haven't changed enough ZR1 rotors yet. I'll bet they haven't changed any, in fact.

Assuming no damage, the rotors need to be weighed and mic'd to determine when they need to be replaced. Period. Nothing else matters. Don't accept anyone telling you that they need to be 'cleaned' (with what?!) before they're weighed or mic'd. Take the rotor off the car, drop it on a scale, check weight, then mic it and check the thickness. The end.

Depends entirely on how you drive, but I'm nearly 100% certain the answer to this is, "Yes, they should".

Weigh and mic all 4.

That seems to make sense, but I don't think there's enough data to show it.

Of course there would be a fee, and probably a substantial one. And fortunately for you, it's absolutely unnecessary. Don't let your dealer (or anyone else) tell you otherwise unless they can whip out the EXACT instructions from GM on the matter. Again, the surface of your rotors should be baby-butt smooth. If they're not, you have damaged rotors.

jas

Rotors and pads have been replaced. I will have more info once I inspect them myself. Thanks for the input. It would seem certain I would have to replace the rotors at some point; I just would have liked it to be later rather than sooner. I believe the explanation was not that the surface of the rotors needed to be cleaned, just that all of the debris stuck in the cross drilled holes need to be cleaned out to get an accurate measurement of weight. One of the front rotors apparantly has some gouges in it. I have not seen it yet.

JVP and others: does anyone know the current weight of their rotors if they have had the pads replaced recently? I realize there are a bazillion factors re: driving style, track, PTM, etc but replacing my first set of pads after 18 sessions does not seem completely out of line with other's experiences. Replacing rotors after 27 sessions and replacing the second set of pads after 9 sessions does seem out of line.

I'll also say that I am fully aware that safety is the priority; running until the brakes are just about to give out is not my goal either.

Ouch. I'm sorry to say, but you've just been taken advantage of. I'll bet you the cost of a rotor that you didn't need to get them replaced. Further, your dealer almost assuredly charged you full price for them; RichieRich here on the forums would have saved you a bunch of money on the rotors and the pads.

Again, that's absolute hogwash. IF there was a debris-in-the-holes concern, a full-power blast from a hose would have taken care of any of that. And that's something you've likely already done when washing your car.

From what?!

I do my own pads, and no I haven't seen the need to weigh or mic my rotors yet. I've only been on the track for 4 days (times 3-4 sessions per day).

Of course. I still suspect you're being taken advantage of and the dealer just made a ton of money off of you. However, your full peace of mind may very well be worth the money you just spent. If so, then ignore me. :)

jas

I agree with JVP on a lot of this.

Sounds like they are not sure what is going on, and do not feel like trying to figure it out either.

We are now on 2 1/2 years of street and track use on Lou's ZR1 with a number of track days and a few runs up the hill as you have seen. We are up to 12,000 miles on the car street and track both and I am still on the OEM set of pads and rotors on the car.

Cleaning and weighing the pads should be able to be done at home if you have the tools to remove it from the car and a accurate scale. Shouldn't be much more than a wash and blow out with an blow gun.

Running the car in the PTM modes is most certainly going to put more wear on the brakes, that I know just from all of the other cars in the past and how it uses the brakes to help it. That is one thing that differs with our car in that we run it shut off or in 5 (race) mode so there is very little interaction from the factory brakes controlling it as the car slides.

As for the vibration...not sure if that is coming from the brakes, wheels, tires, or something else. What did they actually do? I have had wheels and tires that balanced and still had a vibration if there is something wrong with the tire, it has a flat spot, or the wheel isn't mounted to the rotor flat.

Now if they actually did put on all four rotors, new pads, balanced the wheels and tires and it still has the vibration I would look into how the vibration occurs.

1. Speed or RPM related?
2. Load or coast?
3. gear related?
4. Change wheels and tires and try again

I have purchased from Rich before and I agree his price is excellent. I had the service done at a forum dealer and he matched Rich's price.

I have moderate HPDE experience (35 days, 4 schools), and I push pretty hard, but I ran in sport mode for the first 4 days and PTM 3 for the last 2. I am sure that a pro driver like Lou Gilotti uses significantly less braking and far more skill than I, but it is good to know that a great driver can get much more wear out of these brakes than I did. Is he really on the first set of pads and rotors? Wow. Hopefully as my experience increases I will abuse the car less.

I will see the components tomorrow when I pick up the car and head for Road America. If I continue to track this car, I will use up these components anyway, but this situation has been more than a little irritating. The vibration issue will be examined on the way to WI.

I know 10 or 11 planned track days in the first few months of ownership requires a tolerance for high maintence costs. I picked up my Z06 at NCM on a Friday in May of 2008, drove it home for the night in Chicago, then straight to Autobahn in Joliet for Katech Track Attack (510 miles on the odo at the start of the weekend) Sat and Sun. By Sunday the stock pads were done.

All the input is appreciated.

I remember a couple years ago a guy on Ferrarichat that would replace his Enzo rotors about once every 6 weeks with track days every weekend so no they dont last forever. But people like Lou and Spring Mountain seem to be able to make them last.

Just out of curiosity, what is a set of pads and rotors going to run?

Ian

:bigears

Depends on what you call hard on brakes.

He doesn't spend a lot of time on the pedal no, but he does late brake and he is on them hard when he is on them. So they see a lot of pressure and temp, just not for long periods of time.

Draging your foot on the brake increases the amount of friction going on with the brakes and also reduces the cooling time they will see on the straights and thus more wear.

For all you track guys, are you changing your brake fluid before you track the car? The reason I ask is I thought the CC brakes produce a lot less heat than metal brakes? Thanks!

I have a new Z06/Z07 that I will have tracked 4 or 5 times before year end. I changed to GM DOT 4 brake fluid before the first track day. Other than that my car is completely stock. I've also noticed, after the first two track days, some darkening of the clutch fluid so I've started cycling the same DOT 4 fluid into that hydraulic circuit, as needed, using the procedure described by RANGER on this site.

There is no difference in the heat put into the different braking materials. The heat is completely a function of how much energy is in the car when the brakes are applied and how much energy remains in the car when the brakes are released (weight, speed, time). The difference is in how the materials perform at high temperatures and how well the materials and system (ventilation) dissipate the heat.

FYI,

I had a vibration/rattle at 10-50mph that would improve at higher speeds. Sounded like the lugs nuts were loose.

Turned out to be the stabilizer links, an easy fix.

Got home last night from the Corvette World Tribute at Road America (see other threads, a serious good time) and I have not had time to do a full exam of the parts so far but I can tell you that the vibration I had is gone. Very acceptably smooth on the highway. I had had the wheels road force balanced but it did not fix the problem. New rotors did. I will have more info re: the rotors, etc as I have time to examine the parts, etc. I have seen info on the web that some rotors were delivered from Brembo without being validated as being true and this would lead me to believe that may be the case.

As to the brake wear, a quick look at the pads confirmed that the front pads were likely done (after 9 sessions!). The rear pads will be used again.

In terms of how to tell when the pads are done, clearly you don't want to wait on the exposed brass to tell you it's time. I have been told both from a reliable race shop and some guys with GT3RSs and more experience than me that when the pad gets down to the thickness of the backing plate it's time to switch.

Thoughts?

:lurk:

PM sent, would you like to sell the old rotors.
Mike

Do you still have the old rotors? I would be curious to see what they look like, what they weigh/measure and what made the marks on them. I've only sold a couple sets of rotors for reasons other then damage from taking wheels off or the pads going away and not having the indicator light come on.

Spring Mountain just ordered a set of fronts from me to serve as spares for the first time since they've had the ZR1's out there. I think he said they had over 10k miles of pure track time on these rotors. That probably equates to 5k-6k of really aggressive tracking for what some of us do because many of the students do not drive the cars as hard as some of us would.

I've got a 2008 Z06 and these brakes seem like the natural system for track days.

Is this not the case?

VIR is the track, pretty high speed straights.

Thanks,

Ken