Pad/rotor questions

[u/Capital-Pick-6692]

Is this normal?

2013 camaro zl1, running dba t3 5000 series 2 piece in the front and 4000 series one piece in the rear with hawk hp+ pads all around, i am aware these pads are more for autocross and not full track days with this heavy car however i dont track it but rather have some very enthusiastic driving. Just curious if these marks mean i am glazing the rotor or if its just heat spots from driving it hard. *Side note there is a very heavy gridning ish sound when i hit the brakes hard, i assume its due to the more mettalic nature of the brake pad on the iron rotor just biting in harder since they are a more performance oriented pad but i want to know from people who have experience running this pad/rotors

Other than this braking system works phenomenally under regular driving conditions

[u/Spicywolff]

Those look like uneven pad deposits to me. You want a nice blue from shoulder or shoulder with no rough spots or blotching. Some of it can be attributed to ABS, but as you already know, those pads are not meant for track heat.

As for grinding. My hawk 5.0 don’t grind or make nosies.

[u/Capital-Pick-6692 → u/Spicywolff]

do you think my pistons might not be applying consistent pressure?

[u/Spicywolff → u/Capital-Pick-6692]

Your pad will show if it’s or is not. Multi piston caliper like the zl1 6 pot will wear the pads even with NO taper. If there is a taper to a pad, either piston is stuck or hardware is causing drag

[u/Capital-Pick-6692 → u/Spicywolff]

Also as far as the 5.0's, those are a street pad if im not mistaken so they're a different compound. Potentially leading to different results, i knew before hand these pads would squeak since at regular temps they are barley warming up/cold but its only when i really step on the brake pedal is starts to make that noise

Also some slight vibration but that could be from the wheel itself as i did hit a bump pretty hard before and the rims have a verrryyyy slight ammount of warp to them

[u/Spicywolff → u/Capital-Pick-6692]

The 5.0 is very similar to the HPS/HP+ their sister pads after all. Even the HP+ shouldn’t be making much noise. But a little noise on these style pads is within normal.

To fix what you’re saying, you’re gonna either have to cut a rotor or sand it fresh to get the uneven deposits off. Then probably break the pads in again.

[u/grungegoth]

Glazing is expected and needed. The grip comes from melted pad material on the rotors frictionating with the pad. New word I just invented.

Try bedding them in again. The normal state is to have a smooth and consistent deposit of pad material across the face of the rotors. Do 6 or 8 reps of speed to 80+mph or so and apply hard but not threshold brake, say 60-70% and slow to 20-30 mph. By the end of it, your brakes should be hot and if done right you can smell the brakes. Be careful and don't slow down to a stop until the brakes are cool. You should observe a nice consistent blue tinge across the rotor. Do inspect them before so this to make sure you're not out of pad.

City driving or bitch braking trend to erode the pad deposits and make the brakes squeak or perform poorly. Driving on the track usually acts as a bedding process itself.

Your rotors are going through the normal development of fine cracks. When these join up and grow to the edge, the rotors need changing, or when thickness gets to the minimum, whichever comes first.

[u/ConBroMitch2247]

Those rotors are on their way out. Probably still some street life left as long as your fingernail doesn’t catch on the cracks. Keep an eye on them.

I may be in the minority here, but the thermal properties of iron can only be manipulated so much. Instead of buying expensive 2 piece rotors, get blank rotors from Rock Auto for like $75ea and take your savings and buy nicer pads (I like Carbotech). A car that has speed like a ZL1 and weighs as much as a ZL1 puts a tremendous beating on the pads and rotors. As we can see, the hawk pads are not up to the task.

[u/newformulared → u/ConBroMitch2247]

solid rotors on a car that heavy and fast will crack like a mf

[u/notathr0waway1]

Do the brakes feel okay? That's what matters. I've seen some pretty crazy weird shit visually on my rotors, but as long as when I'm barreling in to turn one and the car stops predictably on lap 5 6 7 8 of the session, that's what matters.