Quickshift_C5

My car has the AP Racing Radi-Cal front brakes with Carbotech XP20 pads.

I recently did a track day at Road America, and the whole way back my brakes were squealing when moving. Doesn't matter if it's low or high speed. The sound goes away as soon as I touch the pedal, and it's pretty loud and irritating. Just to be sure, I checked wheel bearings for play, rotated the front pads, took out the normal retainers and put in the spring pad retainers, and did an overall brake inspection of both sides of the car. The squealing stops any time the brake pedal is pressed. This is the 2nd season with these brakes and they've been quiet as a mouse until the last track day. The only change I've made is swapping from Ferodo DS1.11 to Carbotech XP20.

I'm driving 8hrs to Mid Ohio this weekend for a 2-day event, and the squealing is pretty darn annoying. Any thoughts on what I could check or do to see what's causing it or get it to stop? There is nothing I've found indicating any kind of issue or safety related. It's just simply making a hell of a lot of noise. If someone else has been using the XP20's and it's somehow a result of that pad combo, I'd like to know that as well.

blackbeast99

Quickshift_C5

So it's just a function of the XP20 pads specifically? Have you used them? They were quiet the 5hrs to Road America.

If so, that's pretty disappointing. The Ferodo DS1.11's were whisper quiet.

Also, just to be sure...this is when moving, and it goes quiet when I hit the brakes. Which is generally the opposite of standard behavior.

sccaGT1racer

My 20's would only make noise when hitting the brakes when not up to temp.

blackbeast99

MySR71

Don't those calipers have anti-knockback springs?

Quickshift_C5

Yes, should only make noise when pressing the pedal. That's why I'm here. I'm lost!

Yes they do.

Adam@Amp'dAutosport.com

If it is happing when driving there is some issue?? The pad will make noise when applying the brakes but should be quiet while driving. Have you tried cleaning out the brake dust from the caliper..

MySR71

So could the anti-knockback springs be putting enough pressure on the pads (keeping them against the rotors) to make them squeal even if you aren't on the brakes? Maybe they are extra sensitive to making noise if they are too cold or the transfer layer has been removed.

Quickshift_C5

Could be. Only reference are the Ferodo DS1.11 on there before. Those didn't have an issue.

Bill Dearborn

Usually pads will squeal under light pressure. The Carbotechs may be a little more sensitive to pressure than the Ferodo's. On the grand scale of things it isn't a big deal. You more than likely will remove the pads once you start using the car on the street.

Bill

STANG KILLA SS

bingo. track pads squeell the loudest when cold and when tiny/light pressure is applied to them. if that spring is keeping a tiny bit of force pushing the pad to contact the rotor, thats your issue.
sucks ***** for the crazy price they ask for those.

JRitt@essex

It's not the AKB springs. Your answer is above, as pads are the culprit when dealing with squealing noise the vast majority of the time. The AKB springs wouldn't impact one pad set but not another. The Carbotech's have a different material composition and are more prone to noise. They tend to be more aggressive on the discs than Ferodo compounds. They're the primary source of the noise difference.

synner

Did you use high temp lube on pins and backing plates. Although I tend to experience the same thing. Prior to track day quiet, after loud until i reapply. I believe the lube getting cooked off contributes.

Fulton 1

A few years ago I had a similar issue that would show itself only under normal street driving conditions. This was with the AP Racing CP5060 calipers and Carbotech XP10 pads. In my case the noise was a "chirp chirp chirp" coming from both front wheels. Frequency matched wheel speed and it would go away immediately if I touched the brake only to come back when I released the pedal. It didn't generally show itself until about 15-20mph and would sometimes go away for a short time only to come back randomly after a stop.

I tried a few things to troubleshoot it including swapping pads inboard to outboard and LH to RH, thoroughly cleaning everything, checking all of my clearances to be sure there was no rubbing or contact, and tried re-bedding the pads all to no avail. My wheel bearings were SKF's that had just been replaced a year or so prior so I was confident they didn't both suddenly start making noise. Finally, I just decided to install a fresh set of pads and that did the trick - the noise was gone. I ended up switching to the DS1.11s not too long after that, but the noise never did come back.

Quickshift_C5

Same exact noise I have.

I just did 2 days at Mid Ohio without a problem. The noise has never gone away, but I checked everything 100% and was convinced it was just the pads and it wasn't an actual issue.

blackbeast99

Sweet!

drewz06

I'm using hawk dtc for my daily and I get the school bus break sound when lightly stopping

this is with stock calipers

when braking at more than 20 mph I get no noise

I get no noise when slowing without brakes

Quickshift_C5

Fulton 1

Glad you got it solved and good choice on the pads. The DS1.11s have worked great for me.