At wit's end with RacingBrake 2-piece rotors

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At wit's end with RacingBrake 2-piece rotors

Postby JustinM509 » Thu Nov 30, 2017 4:15 pm

I'm having hideous NVH issues with my RacingBrake 2-piece rotors, and their support has been worse than useless. Really hoping someone here can help me.

Before I bought them, I called RB asking if the OE pad would work with them. RB said it would work. It didn't. There was massive pulsation under braking when warm. I tried cleaning the rotors several times per their instructions. It helped for a few hundred miles, and then the problem gradually came back. Eventually, RB changed their tune, saying maybe the OE pad wasn't okay after all (oops, I guess). Porterfield was on their list of compatible pads, so I called them asking if the R4-S would work. Again, they said repeatedly that it would. I also called Porterfield and Good Win with the same question, and both gave me the green light. So I cleaned the rotors again and tried the R4-S. Same story: okay for the first few hundred miles, then NVH would start building up again. I cleaned the rotors AGAIN, with the same effect. The only difference is that instead of a steady pulsation, it's now a rumble that occurs when braking at 40+ MPH. But it's bad, and I'm genuinely worried about what it's doing to my car (not to mention my sanity).

It's also worth noting that whenever I contacted RB by email asking for advice, they were hugely evasive and often unresponsive. They only ever gave me real advice by phone. If that isn't suspicious, I don't know what is.

This was a $750 set of rotors after shipping, and RB isn't giving me a way out that doesn't involve pissing away even more money. I've already ruled out other problems with the suspension and brakes (all original and recently inspected), so either the rotors are defective or their directions were wrong; either way it's their problem, but they are refusing to own it. Their last advice to me was to either have the runout checked, or to have it checked locally -- either of which costs me time and money for a meaningless outcome. And I'm really not in the mood to keep throwing $200 pad sets at these rotors until one of them works.

Can someone help me here?
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Re: At wit's end with RacingBrake 2-piece rotors

Postby Brian » Fri Dec 01, 2017 9:28 am

Not clear to me what is going on here. Certainly stock pads are fine, all the street choices are also fine. Sounds like high spots of pad deposit on the rotor repeatedly. If I had same issue I would indeed check runout and if that measures well within tolerance then turn/clean the rotors and start with the R4S pads yet again and really do a serious pad bedding. My guess is you can see high spots of uneven pad deposits? Alternating lighter and darker stains on the rotor? That R4S is soft enough that it should easily bed a nice even coating all the way around if the rotor is smooth and if there is a lack of runout issues. I have a local long downhill road that I do my pad bedding and I go progressively harder 60 to 20 on brake pedal until I reach max on the brake pedal and make them smoke (perhaps 8 to 10 rounds of 60 to 20 to get to them this hot). I can smell them, often see the smoke coming out the wheel wells when it is done right, then cruise around without ever coming to complete stop to slowly let them cool over perhaps the next 15 to 20 minutes of driving (avoid coming to complete stop and if you need to complete stop at the traffic light then keep off the brakes at the light, ideally the end of my bedding puts me at freeway onramp and then I just go 20 minutes down the freeway and back). Leave the car parked overnight (no parking brake) once cool and should be good to go the next day.
Brian Goodwin
Good-Win Racing
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Re: At wit's end with RacingBrake 2-piece rotors

Postby JustinM509 » Mon Apr 16, 2018 3:55 pm

Brian, thanks for your reply. My apologies for not responding. I do appreciate your effort and thoughtful answer.

I had the pulsation problem with and without bedding. The pattern was the same every time: I'd clean the rotors, and everything would be fine for a few hundred miles; then, after the first serious stop on a warm day, the pulsation would gradually come back until braking felt like sitting in a paint shaker. Re-bedding didn't work; I'd have to clean the rotors again. Then the cycle would repeat.

I did see some radial unevenness in the disc finish with the OE pad, but not with the R4-S. Neither pad produced visible pad deposit spots like I've seen in pics.

I've since gone back to OE rotors and the problem seems gone for good. Oddly enough, pedal feel and initial bite seem slightly better, too. I had regretted purchasing the R4-S, but it seems fine now, so that's a bonus. Either way, problem solved, and a very expensive lesson learned!
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