Pad Rotor Problem AP Disks
 

Background:

Last year we installed the Sprint AP kit. After installing the DS2500 pads they were bedded properly and then tracked, super quiet great stopping.

However after a few weeks as the bedded layer wore off, attempts to re-bed never worked and brakes were like Freddy Krueger clawing at metal. Tried switching to different pads, nothing worked all noisy.

Then at the end of the year switched to Carbotech 1521s which were quiet until they got heat in them.

As it turns out seems like the rotors were warped/wavy.
https://lh5.googleusercontent.com/-4...o/IMAG2279.jpg




Question:

So got new rotors, I nstalling today, however the 1521 pads that I am re-using are not perfectly smooth and took on the wavyness of the old rotors. I tried to sand them smooth, but still a bit wavy to the touch.

Can I install the 1521s re-bed and will they smooth out or will they damage the new rotors?


Cleaned Up and Drying
On drying rack. New Rotors, cleaned hats, calipers. Re-using 1521s.

https://lh6.googleusercontent.com/-m...o/IMAG2277.jpg

I have only used DS2500 since having Sprint Kit fitted and I'm now on my 2nd set of front pads. My front discs are quite wavy as well and squeal like a stuck pig if I haven't tracked for a while. That is, after a week or so of being quite after a track day they start to squeal again. Other people have mentioned the same set up without squeal.

It must be rotor shock from the pads on the street?

Where is @JRitt when you need him? I am planning on fitting AP racing front and rear BBKs this coming weekend to my car, so would like to know his comments / advice

Edit - I love you brake kit washer!

He is over on m3post now selling the new kit for the E92/E90 M3s. :lol:

I talked to him Monday about it, just ordered new Rotors and got his recommended Hawk HPS pads for street.

I think what it boils down to if you are in a colder climate where you can't heat these things up, you have to always run a street pad no matter what then swap at the track. I mean it's common sense of course.

But the rotors seem to not be very tolerant of heating and cooling cycles.

It sucks that the rotors are trashed and my 1521 Carbotechs are all wavy from bad rotors.

But this season going to start with new rotors and street pads and see how they hold up. This is a competition brake kit, so running them for street duty as well may not work in the long run. (Despite trying)

I'm jealous, My wife would murder me if I ever use the dishwasher for that.

Let her go "shopping" for the day. Problem solved. ;)

Mine sound like a pig all the time regardless of pads.

The PMU 999's from @CSG Mike were quiet for about 15 minutes though after bedding. That's a record for my car.

I daily the Hawk HPS+ and haven't noticed any issues in rotor warpage. I switched to the DS2500 for the track day and once hot they squealed like crazy but never faded. Swapped the HPS+ back in after the track day, and they bed just fine.

I will say you need to watch out when the HPS pads are cold and wet. They are like wood. Cold they are ok at best, wet they are ok at best, cold and wet? That combination is like rubbing 2x4's together trying to start a fire.

I second all of that, I am on my second set of rotors running only the HPS after running the C300 AP pads with the original Sprint kit rotors. while they were wonderful on track, the street driving simply destroyed the rotors running those pads. As you said, the HPS are virtually useless cold, but they are near silent on my setup on a new set of friction surfaces. As I will not be tracking the car anymore I am content with it the way it is and just take it easy on the brakes when they cold. While swapping pads would be cheaper then purchasing a Miata or something else at a similar price point for track use, I think long term it is still a better option for me. Also a good excuse to buy another toy. :D

Grooves that run radially are normal...

Do the AP Racing S100 pads work well and not make noise? Any one know their temperature range?

I'll get a picture of the 1521s they were not groves more totally uneven accross the entire surface. You can feel it with our fingers too. Very wavy.