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Brake Rotor Wear

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Old 07-31-2006, 05:01 PM
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Default Brake Rotor Wear

Greetings all! I am still in Germany but leaving here in early September for good. It'* been fun but time to move on and head back home.

I have a quick question about the brake rotors. Specifically the front. My car is an early 2004 GXP. Last summer, with the help of this forum, I switched to ceramic brake pads and the dust was gone. I loved it and didn't notice any braking difference.

About a week ago I started to notice a little squeak from the front brakes as I was driving slowly. It goes away when I turn the wheel slightly in either direction. I cleaned the wheels like I usually do and it went away for a day or so. Today I looked at my rotors up close and I am noticing what looks like slight cracks on them from the top all the way down till the center. Lots of them. They are not really big and the rotor is still smooth. Does anyone have an idea what causes that?

I clean my wheels fairly often with wheel cleaner and a high pressure wash and sometimes the rotors are still pretty warm. I hate that but the nearest place to clean has me drive the car about 5 miles to get there and of course the rotors stay hot for awhile. But another question I have is this. When switching to ceramic rotors, is there an increase in rotor wear or should we also switch to a different rotor form what the factory gave us. The car has a total of 29,000 miles on it now. Mostly stop and go city driving but also autobahn trips with occasional high speed braking..

With my car being put back onto a ship to head to Florida on 2 September, I am trying to wait until any repairs if necessary. Mainly because I don't think I'd have the time to order new rotors and pads that will get here in time. If I take it to a brake shop or the Opel dealer and he says the brakes need replacing, German law requires them to not let me drive it. I know, it'* all for safety but brake jobs here can run almost $1,000 in Berlin. I'd rather have the brakes done in the states.

So, does anyone know if ceramic pads require a different rotor and do they promote accelerated rotor wear? And do any of you think replacing rotors at 30,000 miles is unusual?
Old 07-31-2006, 11:11 PM
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From everything I've read, ceramic pads are suppose to be easier on the rotors because of the absence of abrasive steel and copper in OEM semi-metallic pads. But I wonder if they cause higher rotors temps , possibly slotted rotors might work better with ceramic? Although I havent found any references to a heat problem as of yet. It'* hard to believe that something doesnt have to give. Your hitting hot rotors continously with water could very well be the problem and when I'm in town and hit a car wash (not often) I do the same thing. Will W has alot of data on brakes and I hope he will chime in. Thanks for the input Obis and I am going to stop hitting mine with water while on the go. I would replace them ASAP.
Old 07-31-2006, 11:17 PM
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Sound like heat cracks, and from being in Germany, I'd imagine you've run that baby down the Autobahn a few times or so (hell I'd do it daily lol)

But high rotor temps cause it....

Do they contribute to your squeak? I highly doubt it.
Old 08-03-2006, 12:50 PM
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I had surface spiderwebbing on my 87 turbocoupe (semi-metallic pads) for years with no ill effects. At one point I had them machined, which appeared to have removed the cracks, but they came back. And I put another 40k on those rotors after that.

I guess the concern here is a catastrophic failure of the rotor. Most owners don’t inspect their brakes regularly, especially when the car gets older, but I’ve not heard of this causing a catastrophic rotor failure…but I suppose it could happen.

I’d just wait until I was back in the states, but your car, your call.
Old 08-03-2006, 01:26 PM
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Here'* a very detailed and interesting article on rotor technology. It seems to indicate that you may have heat stress cracks on your rotors.

Disc Brake Rotor Technology

Cracks are another concern with rotors. Cracks can form as a result of poor metallurgy in the rotor (too hard and too brittle because the rotor was allowed to cool too quickly during the casting process), and from excessive heat. Some minor surface cracking is tolerable and can often be removed by resurfacing, but large cracks or deep cracks weaken the rotor and increase the risk of catastrophic failure. So cracked rotors should always be replaced.
I checked a couple other sites too and there seems to be a concensus that, unless your rotors were cast incorrectly (unlikely), surface cracking is usually caused by heavy prolonged braking or a dragging pad. It is mentioned a couple times that a bad caliper can cause pad dragging (which BTW can also cause a squeal/squeak).

Hope this helps.
Old 08-03-2006, 03:18 PM
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Both of my front rotors have done this with stock, RSM, and Powerslot rotors. They're very small micro-cracks that you have to really look for. Consider it normal.
Old 08-03-2006, 03:26 PM
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I've got Midas rotors, and Midas ceramic pads. No cracks for 80k miles.
Old 08-03-2006, 04:13 PM
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I'm talking microscopic surface cracks. Just in the harder out layer. You REALLY have to look. This is typical on hardened rotors. Probably not OEM rotors.
Old 08-04-2006, 07:04 PM
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Default A big help!

Thanks for all the input everyone! After doing a closer inspection, the cracks are small and not all of them extend all the way to the center. The squeaking is still there so I will have a place do a quick inspection on the calipers.

Unfortunately, the Germans do not turn rotors. They told me several years ago all shops stopped doing this. Whether it was industry wide or what I don't know They said if the rotors are worn emough to be turned then they would be replaced. Not sure why, but every place I went to said they do not turn rotors. Maybe German rotors are not as thick. I do think brake requirements on German cars are higher because of their autobahn speeds and maybe they just feel it'* safer to replace than to turn them.

I was looking into the Power Slot rotors when I return to the states but if I can have these turned then I will do that. When I first posted I figured the rotors were dead for sure so I figured I might as well get different ones. But after reading some articles and input here I think I may be fine. I'll see what the Opel dealer thinks as well.

You know, I still get looks of shock from the Germans on the size of the rear brake rotors. Mainly it'* because the wheel is big and has alot of open space and they see this tiny rotor. The relationship to the wheel vs the rotor size is what catches their eye I guess. Hey, thanks again everyone!
Old 01-04-2007, 05:16 PM
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Default Looking at these Rotors

Greetings all! Well it'* been awhile since I posted. I had been in Germany with my GXP for 2 years and had a blast. Now I am in Florida and actually made an around the country trip from Oct - Dec and put 9,000 miles on my GXP from Key West to LA and everywhere in between. Car ran great but I still have some brake squeal mostly on the passenger side front. The Opel dealer in Germany inspected everything before I left and said all looked fine. So I am not worried but I was wondering if any of you have heard of this company and their products.

http://brakeperformance.com/site/bra...load=1&sort=3a

The slotted and drilled rotors caught my attention. It would only be for the front as the rear brakes are fine. Any thoughts?


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