freaknbigpanda

So I took my car to the track today and had a pretty long session (1.5 hours) of constant lapping. I wasn't getting any fade or any abnormal behavior while I was on the track but when I got off the track and the car had been sitting for about 15 minutes I tried to start it again and the brakes were totally gone, i.e. I could press the petal all the way to the floor and got nothing at all so I pulled on the emergency brake and let the car sit for awhile. When I tried it again the brakes were working but now there was a grinding noise coming from the right rear wheel constantly. When I got back home the right rear rotor was gouged pretty badly but the other rotors look OK. It still sounds awful when I drive it.

Does anybody have a good guess as to what happened and what I will need to do to fix it? I'm guessing I will need new rotors and pads at the very least but maybe a new parking brake as well?

tldr: took car to track, brakes got ****ed, need help.

FAUEE

Did you sit on the brakes or set the parking brake when you came off the track?

My bet is you set the parking brake and welded it to the rotors.

Patsgarage

Sounds like hot pads + hot rotors = this.

Freak3150

Doesn't the C6 use a drum on the back side of the rotor for a parking brake?

If that's the case, how would the parking brake affect the pedal, or weld the pads to the rotors?

franman69

Never set your parking brake at the track... It is now permanently on... Why your brakes didn't fade on tracks (after 1.5 hours??) but stopped working 15 mins later......? If the pedal goes to the floor this is typically over heated (boiling) hydraulic fluid... doesn't make sense though 15 mins AFTER your session... hmmm.

freaknbigpanda

This is what I think happened too, if this is the case what parts will I have to buy to fix it? Edit: Just for clarification I did apply the parking brake right after I got off the track Just out of habit when I park

freaknbigpanda

It might have not been 15 minutes, maybe more like 5-10 minutes I didn't time it. And yes no fade for 1.5 hours of constant racing, I think there are brake ducts to cool the rotors right? I was going pretty fast so they should have been getting lots of air, would that not explain why I wasn't getting fade on the track but they failed right after I got off?

AORoads

I'm fairly certain that if you ask here or in Auto Road Racing section you'll get about the same answers. Namely, you'll need pads, rotors and new fluid. No idea about parking brake but doubtful about need for new one.

Just a note for you to research in road racing: most who go to the track will do several things to prepare for hard use, fade or no fade on the track or after. Most will drain and fill the fluid before getting on the track/going to the event, and do it again after the event. Most will have higher grade (temp to boil) brake fluid which is more expensive generally than regular brake fluid. Most will have dedicated track pads, and street pads that they will switch out. And most will cool down the car with only light touches to the brakes. Before your next outing, it may be a wise thing to read up on what to do as well as what not to do, or you may be replacing everything again.

Dano523

Ditto, sounds like you did not drive a few cool down laps, but instead pulled into the pits with the rotors still glowing, and just cocking the pads and Boiling the fluid with the car now at a stand still without air moving across the rotors to cool them back down.

As for the E brakes, the shoes may still be fine, but sounds like you cooked the return springs from heat transfer, and why the E brake C shoe will not retract back from the inside of the rear drums.

When you are replacing the back pads and have the calipers off, pull the rear discs to take a good look at the E brake drum and shoe inside the discs.

freaknbigpanda

can I get by just replacing the rotor that got gouged by the parking brake or do I need to replace all 4? The parking brake seems to have only fused to the right rear wheel.

freaknbigpanda

Hmm if the parking brake uses a drum I may have another problem on my hands because the right rear rotor is definitely gouged. Arg.

FAUEE

Take some pictures of what you've got going on. You should be able to replace just the rear brake parts - I'm not sure I would replace just the right or left side stuff however.

The brake ducts work really well, I didn't have any brake fade in my track sessions either. I did get some tire greasiness near the end of the day on my PSS tires.

choprfgr

Someone please explain how the parking brake gouges the rotor.

The brake fluid boiled and the brakes were gone - stopped boiling
but the caliper was hung in the back or was worn out racing and just not noticed till the mishap. Unless the OP is mistaken about the gouged rotor
and maybe the Ebrake shoes are stuck - it does happen.

LFZ

You are not running DOT4 either...I assume? Yea...definitely need better fluid if you're going to track .

gfacter

Heat did them, in boiled the fluid and probably cooked the rotors real good too, look for heat cracks on the rotors.

You probably melted the dust shields on the calipers and take a look at the steering knuckle near the front rotors

Anyone beyond a first time novice needs to use some hi temp fluid and should really look into LG spindle ducts and proper cooling for extended sessions.

Its always a good idea to try to get a good cool down lap and even a few laps around the paddock to cool the brakes

Never use the parking brake

jackcasual

What track were you at? Did you have an instructor? Usually 1 of the first things mentioned is not to set parking brake. Was same brake fluid used at previous events? Always arrive at event with fresh brake fluid. Always bleed brakes before event. Use a high quality brake fluid. Stock brake cooling vents are probably not adequate for 1.5 hrs of track time. Kits to direct air straight to caliper are available. Brake fluid boiled and now there is air in brake lines. I would replace all rotors. Rotors should be treated as disposables when racing. You can always use a good rotor as a spare. I always carry spares to track. Check brake caliper piston seals. They may be destroyed. I rebuild calipers yearly and use stainless steel brake lines. Always run a cool down lap. Good luck getting back to the track.

freaknbigpanda

Here are some pictures of my rotors:

http://imgur.com/SbZWqt4,wz5smMM,7AcpUDZ,Li15uJb#3

The first image is the left rear, you can see it is fairly ****ed. second is left front, then front right then rear right. obviously the left rear needs to be replaced but what about the others?

Dano523

Being that you know that you are going to track the car, may as well change out the rotors to slotted rotors, instead of drilled. The rotors could be blasted and turned to save them for street use, but for track use, start with a new set of rotors. GM designs the rotors with edge tips to draw heat away, and when the rotors are turned, this outer heat draw edges are often machined off.

The slotted rotors will self clear just as well as the drilled rotors, but will not end up spider cracking (at the drill holes).

Next, may as well change the brake pads to race pads as well. But still, your still going to need to drive cool down laps even with race pads.


As for the E brake Shoes, double check if the problem is the springs, or the shoes that got heat soaked and the problem at hand. And as stated, never use the E brake when the rotors are still track hot (even with cool down laps).

Ditto on checking the caliper seals, since they need to be rebuilt as well (unless the calipers distorted, and will need new calipers instead).

Lastly, Dot 4 for brake fluid, and get in the habit of power flushing it between track days. Brake fluid will absorb moisture pretty quickly, and the more moisture you have in the fluid, the faster it's going to boil.

To sum it up, not sure of that damage was done to the brake system from not driving a few cool down laps, or by the hard lapping to begin with , but now need to resolve the outcome of such. But on a positive note, could had been in a mustang with full street brakes, where you just catch the brakes on fire in a few laps instead.

the blur

Last week, I was a passenger in a Chevy Silverado. The truck starts sliding towards an embankment, and the driver is hard on the brakes.
I'm SCREAMING. "OFF THE BRAKES !!!!" "OFF THE BRAKES"

Nope, he didn't listen, and we slide off sideways into a drainage ditch.