warped discs? - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

dejxx · 12-25-2014, 04:41 PM

I have a set of aftermarket discs on my car (Fremax Sloted OEM size discs, Brazilian shop). And ive been running them for a while with no problems. But on the last track day, i tracked with Ferodo DS2500 on them, and now it seems that i warped my discs, but very slightly. There is no stutter when i brake at high speed, or anything like that, only thing i feel is that when im breaking very softly (for ex., stopping at a red light), i feel the breaks coming on and off... like the pads bit the disc hard, then only a little bit...

Warped discs, or other things going on?

thanks!

dejxx · 12-26-2014, 02:31 PM

anyone?

Ultramaroon · 12-26-2014, 02:45 PM

Well, it was Christmas yesterday.

Pulsing under slight braking is the classic symptom of a warped rotor.

Did you check your wheel lug torques after installation? Too tight or uneven will cause problems especially if the rotors get super hot. Also, after hard braking, never leave them applied after coming to a full stop.

dejxx · 12-26-2014, 02:58 PM

heheh true.. sorry!!!

Checked the wheel lugs, but maybe that was the problem...

Also, i never leave the breaks applied after tracking =) mandatory 1 lap cooldown, then roll very slowly to the pits heheh.

thanks!

Ultramaroon · 12-26-2014, 03:53 PM

Even if installed/handled perfectly there are no guarantees. Might just be a manufacturing variation.

Racecomp Engineering · 12-27-2014, 07:42 PM

Most of the time (as in 99%) its uneven pad deposits, not warped discs. A good rebedding will help. If left too long the discs could be toast. Do a google search for the stoptech white paper on the warped rotor myth and cementite.

- Andy

Sleepless · 12-27-2014, 09:38 PM

Driving on the street with your DS2500 should clean off the pad deposits in a few days.

juliog · 12-27-2014, 10:01 PM

Most likely uneven brake pad deposits on the rotors. This can happen at the track if you ride your brakes driving through the pits after a session, when the pads are still smoking hot. Follow the bedding procedure like suggested above to get the pad material evenly distributed along the rotor surfaces.

Ultramaroon · 12-27-2014, 10:46 PM

Quote:

Originally Posted by Racecomp Engineering

Most of the time (as in 99%) its uneven pad deposits, not warped discs. A good rebedding will help. If left too long the discs could be toast. Do a google search for the stoptech white paper on the warped rotor myth and cementite.

- Andy

This is an excellent resource. Thanks very much, Andy.

http://www.stoptech.com/technical-su...l-white-papers

dejxx · 01-03-2015, 11:58 AM

thanks all for the replies!!

Pete156 · 01-03-2015, 01:06 PM

Good brake info.

Thanks fellas

EAGLE5 · 01-03-2015, 02:06 PM

I did manage to warp the discs on my Dodge Neon, within something like the first 5000 miles. That POS was made with bailing wire, hay, and dog shit. Chances of warping an FR-S disc, even aftermarket, are pretty slim. It's all about the pad deposits, no warping.

Ultramaroon · 01-03-2015, 02:35 PM

Yeah, I learned something new. Andy came through with some great stuff!

12-26-2014, 02:45 PM	#3
Ultramaroon not playing cards Join Date: Sep 2014 Drives: a 13 e8h frs Location: vantucky, wa Posts: 32,395 Thanks: 53,053 Thanked 37,228 Times in 19,308 Posts Mentioned: 1117 Post(s) Tagged: 9 Thread(s)	Well, it was Christmas yesterday. Pulsing under slight braking is the classic symptom of a warped rotor. Did you check your wheel lug torques after installation? Too tight or uneven will cause problems especially if the rotors get super hot. Also, after hard braking, never leave them applied after coming to a full stop. __________________ service manuals

12-26-2014, 03:53 PM	#5
Ultramaroon not playing cards Join Date: Sep 2014 Drives: a 13 e8h frs Location: vantucky, wa Posts: 32,395 Thanks: 53,053 Thanked 37,228 Times in 19,308 Posts Mentioned: 1117 Post(s) Tagged: 9 Thread(s)	Even if installed/handled perfectly there are no guarantees. Might just be a manufacturing variation. __________________ service manuals

12-27-2014, 09:38 PM	#7
Sleepless Senior Member Join Date: Apr 2014 Drives: 2014 BRZ Location: Redmond, WA Posts: 639 Thanks: 299 Thanked 392 Times in 229 Posts Mentioned: 8 Post(s) Tagged: 0 Thread(s)	Driving on the street with your DS2500 should clean off the pad deposits in a few days. __________________ Pete 14 Track BRZ (Build Thread) cmslaptimer.com

01-03-2015, 02:35 PM	#13
Ultramaroon not playing cards Join Date: Sep 2014 Drives: a 13 e8h frs Location: vantucky, wa Posts: 32,395 Thanks: 53,053 Thanked 37,228 Times in 19,308 Posts Mentioned: 1117 Post(s) Tagged: 9 Thread(s)	Yeah, I learned something new. Andy came through with some great stuff! __________________ service manuals

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12-27-2014, 07:42 PM	#6
Racecomp Engineering Join Date: Nov 2011 Drives: 2016 BRZ, 2012 Paris Di2 & 2018 STI Location: Severn, MD Posts: 5,517 Thanks: 3,541 Thanked 7,412 Times in 3,032 Posts Mentioned: 310 Post(s) Tagged: 9 Thread(s)	Most of the time (as in 99%) its uneven pad deposits, not warped discs. A good rebedding will help. If left too long the discs could be toast. Do a google search for the stoptech white paper on the warped rotor myth and cementite. - Andy

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