G-Loc Brakes

[gone_n_60]

When you get the noise on a slow stop, is it quiet compound noise or a loud shriek sound?

Just curious as I’m getting the latter from one of my R10s and I’m not quite sure why. Seems to be getting worse as I put more miles on…

Like some others I was getting really bad squealing from my G-loc's R10's bought new for this last track season. I had Hawks before and they didn't squeal that much at all, some light noise at slow speed. But these G-locs got worse and worse, sounded like a broken horse coming into the pits. I swapped back to Hawk and was better, no squealing. For street I switch to Powerstop Ceramics, super smooth. A few folks had recommended G-loc but my experience wasn't the best. fwiw on track they do handle high speed braking well.

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[cth777]

Like some others I was getting really bad squealing from my G-loc's R10's bought new for this last track season. I had Hawks before and they didn't squeal that much at all, some light noise at slow speed. But these G-locs got worse and worse, sounded like a broken horse coming into the pits. I swapped back to Hawk and was better, no squealing. For street I switch to Powerstop Ceramics, super smooth. A few folks had recommended G-loc but my experience wasn't the best. fwiw on track they do handle high speed braking well.

That’s pretty interesting to hear. The experiences seem quite mixed (on the noise front, not performance) so I wonder if it’s just the build quality variations of a small company.
I was surprised the edges weren’t chamfered but maybe that’s a track pad thing

 

[Bluemustang]

So I actually had to switch away from the R10s to the GS-1 compound. After my first track day with them they squealed very loudly. As you use the material it becomes harder with each heat cycle and squeals more. I also found that if you rinse the brake dust off of the calipers and pads with a hose they are quiet for a day or so. If the squeal is too bad for you (it was for me) just get the GS-1 pads!

Edit: I see your saying its only one wheel that's squealing. That is usually a tell tale sign that a piece of debris or a rock got wedged between the pad and rotor, do you see any weird wear lines on the rotor? If not, its possible you got more heat on that side than the other but it's very unlikely.

I could've told ya that from the beginning. Good move.

 

[Bluemustang]

That’s pretty interesting to hear. The experiences seem quite mixed (on the noise front, not performance) so I wonder if it’s just the build quality variations of a small company.
I was surprised the edges weren’t chamfered but maybe that’s a track pad thing

All of the GLOC pads will make noise, in my experience. But the track oriented pads will squeal like a school bus. I use Raybestos street performance pads for street use. They're silent and temp threshold up to 1200F. Could probably use them for autocross even.

 

[NeverSatisfied]

I dailies r18 in fronts for 35k miles-probably 10+ sets during that time

Using the titanium shims from opmustang really quiets them down.

Still an on off switch when cold but they are no where near as loud as other cars I’ve run these compounds in.

 

[gone_n_60]

That’s pretty interesting to hear. The experiences seem quite mixed (on the noise front, not performance) so I wonder if it’s just the build quality variations of a small company.
I was surprised the edges weren’t chamfered but maybe that’s a track pad thing

It's not a a track pad thing. Hawks are chamfered. I actually filed a little chamfer on the G-locs but after a while they really squealed badly especially at low speed. When I come to light slowing down I'd prefer folks notice my bright orange Stang vs. head turning at the constant high pitched squealing coming from my pads. ;|

 

[Jstang23]

It's not a a track pad thing. Hawks are chamfered. I actually filed a little chamfer on the G-locs but after a while they really squealed badly especially at low speed. When I come to light slowing down I'd prefer folks notice my bright orange Stang vs. head turning at the constant high pitched squealing coming from my pads. ;|

I had the same reaction lmao!

 

[Jstang23]

All of the GLOC pads will make noise, in my experience. But the track oriented pads will squeal like a school bus. I use Raybestos street performance pads for street use. They're silent and temp threshold up to 1200F. Could probably use them for autocross even.

I have had my GS-1 pads start squealing, only when braking lightly. Under medium brake pressure they are silent. Have you had the same experience. I was beginning to think I glazed them. This is a picture of the rear rotor. Thoughts @gone_n_60 ? You think that brown stuff is glaze or just rotor wear?

 

[cth777]

I dailies r18 in fronts for 35k miles-probably 10+ sets during that time

Using the titanium shims from opmustang really quiets them down.

Still an on off switch when cold but they are no where near as loud as other cars I’ve run these compounds in.

I’d love to try the shims but I have the four piston brakes and I think the shims are brembo only

 

[Bluemustang]

I have had my GS-1 pads start squealing, only when braking lightly. Under medium brake pressure they are silent. Have you had the same experience. I was beginning to think I glazed them. This is a picture of the rear rotor. Thoughts @gone_n_60 ? You think that brown stuff is glaze or just rotor wear?

My GS-1 began squealing after a time as well. I couldn't get rid of it no matter what I did. Others didn't report the same issue so idk. I tried reinstalling them and even sanding down the rotor surface but it didn't help. The R10/R8 combo squeal was wayy louder though.

I have glazed them on one occasion when I was pushing on the street backroads too hard. And honestly, that surprised me. I'm not sure what you've got there. It isn't rust? How old are the rotors? Rotors can be also worn down to a point where they need replacing and can't be seen by the naked eye. Need to measure the thickness.

I've been very happy with the Raybestos pads and rotors and nobody seems to know about them. For your application, you might do well with another set of rotors to be used specifically for the track. That way you can run whatever pads you want for the street and not have to worry about the mating surface. These are just my thoughts. There are far more knowledgeable folks here than me.

 

[gone_n_60]

I have had my GS-1 pads start squealing, only when braking lightly. Under medium brake pressure they are silent. Have you had the same experience. I was beginning to think I glazed them. This is a picture of the rear rotor. Thoughts @gone_n_60 ? You think that brown stuff is glaze or just rotor wear?

Hard to say without looking at the pads, could be. fwiw mine while newish, only 3 track events glazed over a good bit. But my rotors were getting end-of-life after two track seasons too.

 

[Jstang23]

@Bluemustang and @gone_n_60 I showed the picture to my race shop and they said its just discoloration since it has been raining for the past few days. I thought there couldn't be rust on the rotor as I had just driven them when I took the picture lol!

Shop said no evidence of anything wrong, but told me to look at my pads if I still have squealing after a couple days.

 

[cth777]

@Bluemustang and @gone_n_60 I showed the picture to my race shop and they said its just discoloration since it has been raining for the past few days. I thought there couldn't be rust on the rotor as I had just driven them when I took the picture lol!

Shop said no evidence of anything wrong, but told me to look at my pads if I still have squealing after a couple days.

For what it’s worth, my rotors with R10s on them have a slight brownish hue to them, and they’re definitely not glazed - haven’t tracked these pads yet. I was assuming it’s just pad material

 

[Jstang23]

@gone_n_60 and @Bluemustang I found the problem! They were glazed!!

I sanded the pads down starting with 80 grit, then 120 grit, then 240 grit! The glaze is tough stuff, took a while sanding by hand in figure 8 patterns. I've only driven them maybe 10 miles but the squealing is gone and honestly they feel much better under the pedal!

Before and after pic!

 

[Optimum Performance]

@gone_n_60 and @Bluemustang I found the problem! They were glazed!!

I sanded the pads down starting with 80 grit, then 120 grit, then 240 grit! The glaze is tough stuff, took a while sanding by hand in figure 8 patterns. I've only driven them maybe 10 miles but the squealing is gone and honestly they feel much better under the pedal!

Before and after pic!

If you are glazing them then you are are on them too much. Do you do events with an Instructor? Rotor paint is your friend to determine what temps you are seeing on track. I would just use the most aggressive sand paper and stop there.

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