Trying to get rid of G-Loc R10/R8 rotational and non-rotational squeal
 

So after my brake light switch finally was replaced, I am back to debugging these pads.

Preface:

- New blank centric's, G-Loc R10 (F) and R8 (R) (which are essentially Carbotech XP10/8) were put in with fresh RBF660 all at once
- 1 track day and 600 km of driving elapsed
- Used first 2 sessions of track day to bed-in, nice blue rotors (perhaps not enough?)
- Shims removed on all 4 corners after track day

Things I'm trying to fix

1. Annoying as hell rotational squealing

Pre and post track day, the brakes squeal in concert with wheel rotation. The frequency increases with wheel rotation. The sound level of the squealing is directly relating to how long I've been driving. In the morning they are silent-ish, then by the time I'm at work I sound like a swarm of crickets and birds.

I thought that perhaps the pads were too thick - I removed the shims and they still present this rotational squeal. The pads don't really inhibit the free rotation of any wheel...

Do you guys think the sound will go away over time as the pad will lose some of its thickness over time?

2. The sound of a whale dying when braking

This is relating to the sound when applying brakes. So far, when on the track and when the pads are nice and hot they did not exhibit any grotesque noises. Likewise when I first drive in the morning.

However, rush hour in stop/go the brakes are loud AF. I'm assuming the temps are at some noise inducing range?

Solutions

Is it just a more thorough bed-in again? Which is pretty difficult to do not on a track....

OR

Just buy 1521's (GS-1's)

@CSG Mike
@wparsons

Do you have pics of your rotors? I can tell you if you're overheating the pad (which would also make the noise go away).

Actually, I don't think I would have ever been able to bed my Carbotechs in at the track in my Miata, I always did it on the street (empty backroad). Just too much time between hard braking events when on a technical track in a momentum car on RComps.


My process for bedding track pads on an empty backroad. This is assuming a properly functioning brake system, recently bled with good fluid/lines, etc.

Accelerate to 70-75 -> 10. REPEATEDLY. Back to back to back to back........however many times it takes for the brakes to STINK and the pedal to start going soft.

Gingerly drive home touching the brakes as little as possible, let cool to ambient.

Done.

@CSG Mike

Passenger Front

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Driver Front

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Passenger Rear

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Driver Rear

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For the first problem, how tight are the pads in the caliper carriers, and how freely do the sliders move? It sounds like they're dragging slightly without pressure on the pedal. The noise not being present and then appearing is likely due to heat in the pads. I bet if you listen very carefully you'll hear them dragging at low speeds.

For the second, it sounds like they need to be bedded again.

1. They fit pretty snug and everything was lubed up. I second guessed putting in shims at that point and got them removed.

When I got that stupid brake switch replaced, the very helpful folks at my local Toyota pulled em apart on the hoist and everything looked pretty good. Maybe it's the shape of the pad?

I definitely hear it when rolling low speeds...think TTC bus noises.

2. Yup, I scouted out some roads in my neck of the woods for tonight, hopefully #1 and #2 go away.

If they're too tight, or the slider pins are sticking, the pads will drag more than normal. Mine were doing it until I took it apart and filed down the carriers around the pad ears to remove the brake dust deposits. Now they slide easier.

Sorry to tell you drew, but totalled. Get a part out thread going

@drewbot you need to get a bit more heat into them, judging from the pictures. As @OkieSnuffBox said, get em hot enough that you can smell them, and then let them cool down while rolling, without touching the brake pedal.

Update:

Following @OkieSnuffBox @CSG Mike @wparsons advice, I went and did another bed in. Rotors below

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After driving about 50 km the next day, both issue #1 and issue #2 have been minimized, but are still present. I am completely OK with the sound levels (for now). I wonder how long this transfer layer will last...hopefully until the next track day

I'm running st45 front and st47 rear. First time trying Raybestos pads, but very happy so far. Only 2 track days but lots of street with them so far. Was thinking I might need to switch to something quieter for street driving after experience with race pads on other cars. Thought I'd do everything I could do to prevent having to switch pads. Tapered the leading edge of the pads with cut-off wheel/grinder and used disc brake quiet compound and ultra high temp grease everywhere I thought would help. Had a bit of squealing but definitely nothing terrible. Went back in and added shims and compound/grease in more areas. I get a peep every now and then but overall totally acceptable for me. We shall see as time goes on. Are your pads tapered?

I honestly can't remember but I think they have the slightest of tapering. I have the OEM ones staring at me right now and they appear to be more tapered than these (again I'm not 100% certain).

Tapering the edges can help with noise.
@drewbot you certainly got them hot enough! Under street driving conditions, try braking slightly harder, and avoid "very light braking". That should help significantly.

Ugh the transfer layer is going away on the rears and the sound is back :(