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      08-30-2014, 11:19 AM   #1
badbeef
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Brake question

I took the car to the track a few hundred miles ago and ever since when I'm braking there is a sound which is new. It sounds like all of a sudden the car has some 4x4 tires on it. Here is a picture of the rotors... Are they badly grooved? Any idea what is happening? The brakes are about 12k old.
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      08-30-2014, 11:26 AM   #2
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well, by the look of the grooves, seems like some sand/dust got between friction parts or pressure is not equal on both sides. Does the other side has the same grooves?
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      08-30-2014, 07:06 PM   #3
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Here are all 4. The fronts look similar -- worse than the rears, which also look similar.

I dont know if this is "normal" or not. This is a heavy car, but I am still surprised that 1 day at the track was enough to do the brakes in. I'm certainly not an advanced driver, but I have been on a few track days (~5, but this is the first with this car). Probably more beginner, maybe intermediate on a good day. Not good enough to be carrying super high speeds like a better driver.
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      08-30-2014, 07:20 PM   #4
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feel with your fingertips to see the rotors are not smooth. maybe you warped them. it happened to me when i used stock pads.
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      08-30-2014, 09:05 PM   #5
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I can feel ridges in the front.. rear is much smoother. But the front don't look warped... just ridged
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      08-31-2014, 01:23 AM   #6
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i would suggest to refinish the brake disc and get new pads(pagid or something) if the grooves are noticeably deep.
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      08-31-2014, 08:43 AM   #7
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Looks pretty normal to me?
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      08-31-2014, 08:45 AM   #8
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Quote:
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Looks pretty normal to me?
This

Mine look about the same
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      08-31-2014, 08:47 AM   #9
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If you really use them they will have heat checking all over, 100s of vertical cracks throughout the rotor. Those are fine use them until at minimum thickness.
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      08-31-2014, 05:38 PM   #10
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The pics make it hard to see how deep the grooves are, but from what I can tell they do not look too bad (assuming you have a decent amount of mileage on them).

Can you tell us more about the new "sound" you are hearing? Does it:
a. happen every time, or sometimes?
b. happen when you brake and turn left?
c. happen when you brake and turn right?
d. change in wet weather?
e. happen when you reverse?
f. happen from soft stops only, hard stops only, or both?
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      08-31-2014, 08:13 PM   #11
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These are a few training links worth reading on "brake surface finish" including brake noise:

http://www.procutinternational.com/supplier_gm.aspx

http://www.rockauto.com/info/Wagner/...onTransfer.pdf
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      08-31-2014, 08:46 PM   #12
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You probably have pad deposits from the stock pads. This happens with OEM pads when you get to about your level at the track. This should be worn off in another hundred miles or so and has happened to me and many others. Time to upgrade your front pads for your next track event - it's easy and only takes around 30 mins. Look for a DIY on this forum.
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      08-31-2014, 08:56 PM   #13
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Quote:
Originally Posted by dbyrd View Post
You probably have pad deposits from the stock pads. This happens with OEM pads when you get to about your level at the track. This should be worn off in another hundred miles or so and has happened to me and many others. Time to upgrade your front pads for your next track event - it's easy and only takes around 30 mins. Look for a DIY on this forum.
Doesn't look like pad deposits but shudder under braking would indicate that is the case.
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      08-31-2014, 10:43 PM   #14
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Quote:
Originally Posted by 1MOREMOD
Looks pretty normal to me?
yea looks normal to me too. did you use track pads?
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