Brake issue while on track?

vr46 · 11-14-2019, 02:25 PM

Hi Gents...Trying to problem solve before ZLE goes into dealer for observation.

2019 ZL1 1LE...3000 miles total, last 800 with about 700 track miles.

Drove to track today, about a 30 min. drive, car felt perfect as usual. Was on track and as I built up speed I started to feel a vibration, I believe mainly under braking. It felt like it was getting worse as I kept lapping faster.

I pulled into pits to check tires, thinking maybe the PSI dash gauge was broken and I might have had a flat (all were at 33PSI). Put my hand close to the left front wheel, normal heat, nothing looked unusual. Put my hand by right front and WOW, the heat seemed twice as hot coming off that wheel area.

Let car cool down, headed home, another 30 min drive mainly HWY, car felt normal again.

Warped rotor? Wheel bearing issue? Brake pad problem?

Any ideas?

viurniel · 11-14-2019, 04:04 PM

I experienced something similar (not on track) and it was only debris that the tire picked up. I cleaned the tire up when cool, and solved.

vr46 · 11-14-2019, 04:15 PM

Quote:

Originally Posted by viurniel

I experienced something similar (not on track) and it was only debris that the tire picked up. I cleaned the tire up when cool, and solved.

Interesting, that's similar to what my friend said happened on his race prepped Boss Stang. He picked up rubber inside on the rim as big as a quarter and it threw off the balance apparently. Once he removed it, problem solved.

Is this what you mean? Are you referring to debris on the inside of the wheel itself our something got between the caliper/rotor that caused vibration?

Stephen12ZL1 · 11-14-2019, 04:42 PM

it could be anything listed above...brakes/rotors with material embedded in them or tires with buildup. Keep driving if you don't feel anything serious through the steering wheel.

JeromeS13 · 11-15-2019, 12:32 AM

What PTM/Stabilitrac/Traction Control settings were you using? Was this primarily on a CW or CCW track?

It sounds like you may have some uneven pad transfer and may need to bed your brakes in again. It's a common occurrence when you're using the same pads for street and track.

viurniel · 11-15-2019, 07:27 AM

Quote:

Originally Posted by vr46

Interesting, that's similar to what my friend said happened on his race prepped Boss Stang. He picked up rubber inside on the rim as big as a quarter and it threw off the balance apparently. Once he removed it, problem solved.

Is this what you mean? Are you referring to debris on the inside of the wheel itself our something got between the caliper/rotor that caused vibration?

In my case it was road pebbles 'glued' on one tire. As others mentioned, could also be related to brakes.

Russell James · 11-15-2019, 09:20 AM

I would get an infra red heat gun. Harbor Freight has some cheap ones that work. Do some spirited driving and hard straight line braking. Shoot the rotor temps. Is one way hotter than the other?

Also like mentioned above, watch what mode you are in on track. Too much active handling intervening can really heat up a brake corner. I watched a car once come in the pits with a rear brake smoking. That corner was way over temp from running the track, sliding the corners with full AH. He was trying to slide it to rotate the corners, but active handling was really hammering one corner brake trying to keep the car straight.

Take a peak at the 4 front pads, are they wearing evenly. After a few hundred road miles to get all the track rubber off, wouldn't hurt to have the front tires balance checked. Just to rule out a weight possibly came off.

NorthGeorgia · 11-15-2019, 10:35 AM

Same issue. Was piles of molten rubber that had adhered to the inside of the rim throwing it out of balance. Usually more on one side front and back. I carry a scraper and hit the insides during tire rotations at lunch or end of day. Also agree that less brake intervention and less uneven rotor heat in Track Sport 1 or 2 versus Tour or Track Wet/Dry.

vr46 · 11-15-2019, 05:34 PM

Thx for all the comments.

I just got to the track that day and was on 3rd lap...first two were just cruising around as I felt the "imbalance/wobble" build up as I applied more "spirited" braking. I believe I was in Track - Sport 1 which is what I typically start in (but may have been Track - Dry, on that particular session).

I'll pull the wheels and check for any build up, along with pads and bearings while there.

s.hammer · 11-15-2019, 09:01 PM

If it is only under braking, most likely deposits on the front rotors or warping of the front rotors from your last outing at the track. I have warped 2 sets of fronts so far so it does seem common, (at least for me)

Og Neon · 11-15-2019, 10:13 PM

Quote:

Originally Posted by vr46

Thx for all the comments.

I just got to the track that day and was on 3rd lap...first two were just cruising around as I felt the "imbalance/wobble" build up as I applied more "spirited" braking. I believe I was in Track - Sport 1 which is what I typically start in (but may have been Track - Dry, on that particular session).

I'll pull the wheels and check for any build up, along with pads and bearings while there.

It is called judder. What you are describing are similar to a warped rotor but it is from un even pad build up on the rotors. You probably drag your brakes too much or did a hard stop and let the hot pads imprint on the rotor. Those are two big causes of judder. Google it and you will see what I am talking about.

PS What track was this? I just moved from Phoenix.

vr46 · 11-16-2019, 02:44 PM

Quote:

Originally Posted by Og Neon

It is called judder. What you are describing are similar to a warped rotor but it is from un even pad build up on the rotors. You probably drag your brakes too much or did a hard stop and let the hot pads imprint on the rotor. Those are two big causes of judder. Google it and you will see what I am talking about.

PS What track was this? I just moved from Phoenix.

Thx and I'll definitely look it up. Key question now, if that's what it is, how to remedy it?

As for the track, I'm a member at Apex Motor Club. Here's a post under track section. You'll see my PDR video from it as well.

https://www.camaro6.com/forums/showthread.php?t=564829

Og Neon · 11-17-2019, 07:10 PM

Ok cool. Apex was just opening as I left, sucks that I just barely missed it after hearing about it for years. Looks fun though.

vr46 · 11-18-2019, 01:05 PM

Quick update...Brought it in to dealer, they cleaned the rotors and machined them. Calipers cleaned up as well...no issues so far, so problem solved.

Anyone know how consistent this maintenance is for a mainly track ZL1 1LE?

I have about 10 track days on them...about 4 , 15 min sessions per track day. I understand it depends on the track config, how much braking, etc. Just curious.

Not sure I can machine them again, I might have to replace next time.

Common?

11-14-2019, 02:25 PM	#1
vr46 Drives: 2019 ZL1 1LE Join Date: Jul 2019 Location: Phoenix Posts: 42	Brake issue while on track? Hi Gents...Trying to problem solve before ZLE goes into dealer for observation. 2019 ZL1 1LE...3000 miles total, last 800 with about 700 track miles. Drove to track today, about a 30 min. drive, car felt perfect as usual. Was on track and as I built up speed I started to feel a vibration, I believe mainly under braking. It felt like it was getting worse as I kept lapping faster. I pulled into pits to check tires, thinking maybe the PSI dash gauge was broken and I might have had a flat (all were at 33PSI). Put my hand close to the left front wheel, normal heat, nothing looked unusual. Put my hand by right front and WOW, the heat seemed twice as hot coming off that wheel area. Let car cool down, headed home, another 30 min drive mainly HWY, car felt normal again. Warped rotor? Wheel bearing issue? Brake pad problem? Any ideas?

11-14-2019, 04:42 PM	#4
Stephen12ZL1 Drives: '21 ZLE A10 Join Date: May 2012 Location: Mechanicsville, VA Posts: 6,808	it could be anything listed above...brakes/rotors with material embedded in them or tires with buildup. Keep driving if you don't feel anything serious through the steering wheel. __________________ '21 ZLE A10 Wild Cherry PDR 2:00.78 VIR Full 10.68@131.69 1.68 60' '17 ZL1 A10 Mosaic Black PDR/Nav 2:03.08 VIR Full 11.003@129.2 1.75 (sold) '15 Z/28 #325 Black a/c & stereo. 2:10.1 VIR Full (sold) '12 ZL1 A6 Black 10.52@131 1.55 60' 2:13 VIR Full (sold)

11-17-2019, 07:10 PM	#13
Og Neon Lover of Speed Drives: 2018 ZLE Join Date: Feb 2016 Location: Phoenix Posts: 266	Ok cool. Apex was just opening as I left, sucks that I just barely missed it after hearing about it for years. Looks fun though. __________________ Killer Whale Racing 2021 One Lap of America Track Videos 2019 One Lap of America Track Videos 2017 One Lap of America Track Videos 2022 Ram TRX 2018 Camaro ZL1 1LE 2020 Range Rover Sport SVR (Sold) 2014 Grand Cherokee SRT (Sold) 2014 Camaro Z/28 (Sold)

11-14-2019, 04:04 PM	#2
viurniel @viurniel Drives: 19 ZLE A10, 15 2SS, 90 300ZXTT Join Date: May 2016 Location: Miami Posts: 409	I experienced something similar (not on track) and it was only debris that the tire picked up. I cleaned the tire up when cool, and solved.

11-15-2019, 12:32 AM	#5
JeromeS13 Drives: 2017 1SS/1LE Join Date: Sep 2016 Location: FL Panhandle Posts: 1,559	What PTM/Stabilitrac/Traction Control settings were you using? Was this primarily on a CW or CCW track? It sounds like you may have some uneven pad transfer and may need to bed your brakes in again. It's a common occurrence when you're using the same pads for street and track.

11-15-2019, 09:20 AM	#7
Russell James Drives: '15 SS 1LE, '69 Z28 drag car Join Date: Dec 2009 Location: Mich Posts: 4,483	I would get an infra red heat gun. Harbor Freight has some cheap ones that work. Do some spirited driving and hard straight line braking. Shoot the rotor temps. Is one way hotter than the other? Also like mentioned above, watch what mode you are in on track. Too much active handling intervening can really heat up a brake corner. I watched a car once come in the pits with a rear brake smoking. That corner was way over temp from running the track, sliding the corners with full AH. He was trying to slide it to rotate the corners, but active handling was really hammering one corner brake trying to keep the car straight. Take a peak at the 4 front pads, are they wearing evenly. After a few hundred road miles to get all the track rubber off, wouldn't hurt to have the front tires balance checked. Just to rule out a weight possibly came off.

11-15-2019, 10:35 AM	#8
NorthGeorgia Drives: 2018 ZLE, 2023 C8, IMSA MX-5 Join Date: Jul 2019 Location: Lake Lanier GA Posts: 77	Same issue. Was piles of molten rubber that had adhered to the inside of the rim throwing it out of balance. Usually more on one side front and back. I carry a scraper and hit the insides during tire rotations at lunch or end of day. Also agree that less brake intervention and less uneven rotor heat in Track Sport 1 or 2 versus Tour or Track Wet/Dry.

11-15-2019, 05:34 PM	#9
vr46 Drives: 2019 ZL1 1LE Join Date: Jul 2019 Location: Phoenix Posts: 42	Thx for all the comments. I just got to the track that day and was on 3rd lap...first two were just cruising around as I felt the "imbalance/wobble" build up as I applied more "spirited" braking. I believe I was in Track - Sport 1 which is what I typically start in (but may have been Track - Dry, on that particular session). I'll pull the wheels and check for any build up, along with pads and bearings while there.

11-15-2019, 09:01 PM	#10
s.hammer Drives: 2015 Z/28 Join Date: Jun 2011 Location: Rhode Island Posts: 245	If it is only under braking, most likely deposits on the front rotors or warping of the front rotors from your last outing at the track. I have warped 2 sets of fronts so far so it does seem common, (at least for me)

11-18-2019, 01:05 PM	#14
vr46 Drives: 2019 ZL1 1LE Join Date: Jul 2019 Location: Phoenix Posts: 42	Quick update...Brought it in to dealer, they cleaned the rotors and machined them. Calipers cleaned up as well...no issues so far, so problem solved. Anyone know how consistent this maintenance is for a mainly track ZL1 1LE? I have about 10 track days on them...about 4 , 15 min sessions per track day. I understand it depends on the track config, how much braking, etc. Just curious. Not sure I can machine them again, I might have to replace next time. Common?

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