[Need4Camaro]

Edit: The issue turned out not to be warped rotors but a loose caliper. See post #33

So about a year ago when I got my E85 tune, I had all 4 rotors and pads replaced with stock delco equipment for my first brake job on this car because the pads were low. The stock rotors were not warped at the time, just low pads.

About two months after that, I would feel a shudder whenever I applied light - moderate braking. I later replaced my wheels with 1LE sized Wheels / Tires and went with rebuilt 1LE front calipers, rotors and pads and also had the rear calipers rebuilt, new rotors and pads and for a short time braking was smooth.. but about 1 month later the braking shudder returned.

On the highway I drive between 70 - 85 MPH depending on the road, general flow of traffic and conditions.. ..I am curious if doing 85 for a prolonged time should heat up the rotors enough to warp them if not applying the brakes? I was thinking no... but why am I eating rotors?

[tenargo57]

According to stoptech it's nearly impossible to warp rotors, here's a technical paper from them about it.

If you don't see any cracks or other defects what you're experiencing is likely hot spotting, which is uneven pad deposits that cause them to grab harder at those points. According to stop tech it's usually caused by improper bedding.

I've had this happen before and have done exactly what the paper I linked suggests (for bedding rotors), and it completely eliminated it. Stop from 60 - 5 mph about 10 times total. Start with light braking the first time, the next time brake a bit harder and continually increase braking pressure each run until the 10th time you're slamming on the brakes to the point ABS kicks in. You could also try having the rotors turned down at a machine shop.

[NiickySaz]

Could be a rotor defect.

The brake pad could have been installed incorrectly.

Not sure but, maybe if the wheel wasn't torqued correctly after reinstall?(maybe someone else can chime in on this)

But I'd guess the heat isn't venting properly, maybe trace your steps get under the car and see if anything looks out of place is what I would do. If your caliper needed to rebuilt, maybe it's time to actually just get a new one?

[N Camarolina]

I'll second the pad bedding, as well as rotor burnishing (related). Before you use your breaks aggressively, you need to bed the pads (evenly transfer pad material to the rotors) as well as gradually heat the rotors, then drive for a few miles without touching the breaks to cool the rotors and pads back down. I'd modify the 60-5 mph recommendation by suggesting 5 stops in row from 60-20 with moderate pedal pressure, followed by another 3-5 stops from 75-20 with about 80% brake pressure. You'll know when you've done it enough because the pads will be smoking (you'll smell it) and they will start to exhibit some fade (stopping distance increases with same amount of pedal pressure). After you cool the brakes back down and park it (do not set the emergency brake) you'll see that the rotors will have a bluish gray hue to them near the inner and outer edge and everywhere else should have an even thin layer of brake pad material deposited (dark gray).*

I track mine (lots of hard, threshold braking) so do the above burnishing procedure at minimum every time I change pads and/or rotors. I've never had a problem like you describe. On all my previous cars I haven't ever done a burnishing procedure and never had a problem, but on those vehicles I was really easy on the brakes (coast for a while before even using the brakes, etc).

[JamesNoBrakes]

There's also vibration/resonance/propagation, if your brake system allows pad vibration to resonate, it causes bigger and bigger vibrations that can and does warp rotors. It's usually just squeal, but squeal is vibration as described, I know if situations where it gets bad. This is why the Gen 5 Camaro SS had the "roller skate" brake pads with weights on them, to change the frequency so it wouldn't propagate through the brake system. There isn't always a sure-fix for this, but sometimes worn bushings can contribute or a loose part/axle/bearing. If it's none of that, I'd suspect your pads, are they OEM and have you tried any others?

Bedding instructions come on any pads you buy...

[keep_hope_alive]

the caliper needs to glide on pins, and those pins need to be greased. when you get this shudder it's usually a stuck guide pin and not a warped rotor. disassemble and you may find that the caliper doesn't properly "float" and one side doesn't move easily.

[ctrlz]

Yes, technically it's disc thickness variation (DTV), not warping.
I had bouts with this and I concluded the stock semi-metallic pads were hard on the rotors. I switched to ceramics and the improvement is substantial.

[Gunkk]

Originally Posted by tenargo57

According to stoptech it's nearly impossible to warp rotors,

Improperly torqued lug nuts will do it. No mention of this in the article.

Your Camaro's spec: 140 ft-lbs.

[dpevans]

brembo brakes are they shimmed properly and were the slide pins cleaned and greased that could cause a pad to stick. This would show if the pads are showing uneven wear. You also could have air in the caliper. You could also have build up behind the rotor where it touches the wheel bearing, have you performed a run out with a dial indicator to see if the rotor is warped. I am going with air in the caliper and it needs bled I've seen that too many times. You could have a bad bleeder not allowing the caliper to bleed properly. Good luck and hope you find the cause without throwing a parts cannon at it.

[Need4Camaro]

Eh, where are you guys safely bedding your rotors? If did a 60 - 5 mph stop out here I'd likely have a semi in my trunk.

[arpad_m]

Originally Posted by Need4Camaro

Eh, where are you guys safely bedding your rotors? If did a 60 - 5 mph stop out here I'd likely have a semi in my trunk.

We all have to do our homework on this one, unfortunately...

Last time I did it, I got nauseous from all that repeated heavy 60 to 5 braking of course I accelerated to 60 fairly quickly each time to make sure the rotors don't cool down... hope it was just a fluke, otherwise that's all she wrote about racing the car next year

[Christian1LE]

Just going to throw my 2 cents in here. I used to be really methodical about bedding new pads etc. Now I will just throw a new set of pads in my brakes and I just go out on track and drive hard. I don't do anything special. Same thing when I put on new rotors, I just go out there and drive hard. I've been doing that for 2 years now and I've gone through 2 rotors and through like 14 brake pads.

I know this doesnt apply to street driving but just know that the brakes on these cars arent super sensitive, it can take a lot of abuse. This weekend I had brand new rotors with used brake pads and I "bedded" them in by driving in the rain on track.

[dpevans]

Originally Posted by Christian1LE

Just going to throw my 2 cents in here. I used to be really methodical about bedding new pads etc. Now I will just throw a new set of pads in my brakes and I just go out on track and drive hard. I don't do anything special. Same thing when I put on new rotors, I just go out there and drive hard. I've been doing that for 2 years now and I've gone through 2 rotors and through like 14 brake pads.

I know this doesnt apply to street driving but just know that the brakes on these cars arent super sensitive, it can take a lot of abuse. This weekend I had brand new rotors with used brake pads and I "bedded" them in by driving in the rain on track.

I thought you only had to bed pads and rotors for track events to get the best bite possible. I bed them the day before an event then drive for a week before changing back to street pads and have never had an issue.

[Christian1LE]

Originally Posted by dpevans

I thought you only had to bed pads and rotors for track events to get the best bite possible. I bed them the day before an event then drive for a week before changing back to street pads and have never had an issue.

Did not make a single difference, bites hard either way. May be different if you're changing between compounds for street/track.