Brake Vibration question

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Quick question about brake vibration.

I get pedal brake vibration when braking, which can be felt through the brake pedal, but not the steering wheel.

The thing is that the vibration is much worse when the brakes are hot, e.g. after spirited downhill driving and less noticeable during normal driving.

I had issues with brake vibration a few years ago. Different rotors back then. But also different symptoms. Last time the shake was also felt through the steering wheel and got worse as time passed. But it wasn't affected by the temperature.

I understand that vibration that is felt through the pedal and the chassis points to rear rotors' issues. But what does the increasing vibration with higher temperatures mean?
 
Higher temperatures means nothing significant. Understand when your rotors are warped, the vibration will be more noticeable when the rotors are hot versus when the rotors are cold.
 
Just be sure it's not pulsed brake pressure from Anti-Lock braking systems. That will be pedal feel but not steering wheel feel. ALB vibrations can manifest themselves after spirited driving as the pads & rotors when up to temperature can be grab-ier and need more antilock compensation. More of an issue with disks vs drums.

Cold brakes have a different feel than hot brakes, you may not get much antilock compensation until you press quite hard on the pedal. But since you will naturally compensate for either condition, you may not be aware of the two pedal feels unless you deliberately look for it.

Rotors will warp more when hot, as someone pointed out already. As with anything brake related, it's cheaper to fix problems now versus waiting, if there actually is a problem.
 
Originally Posted By: Charlie2015
Higher temperatures means nothing significant. Understand when your rotors are warped, the vibration will be more noticeable when the rotors are hot versus when the rotors are cold.



I'm not sure that was the deal the first time. It's been a few years now, but I think vibration was pretty much the same regardless brake temperature. It could be felt through the steering wheel back then and was getting worse as time passed and more miles were added to the car.

Originally Posted By: andyd
I wouldn't change the rotors until I wire wheeled off the pad material built up from hard usage,


Could measuring the rotors' run-out eliminate wrapped rotors, but geometry etc. as a cause for the vibration?

Originally Posted By: Johnny2Bad
Just be sure it's not pulsed brake pressure from Anti-Lock braking systems. That will be pedal feel but not steering wheel feel. ALB vibrations can manifest themselves after spirited driving as the pads & rotors when up to temperature can be grab-ier and need more antilock compensation. More of an issue with disks vs drums.

Cold brakes have a different feel than hot brakes, you may not get much antilock compensation until you press quite hard on the pedal. But since you will naturally compensate for either condition, you may not be aware of the two pedal feels unless you deliberately look for it.

Rotors will warp more when hot, as someone pointed out already. As with anything brake related, it's cheaper to fix problems now versus waiting, if there actually is a problem.


No it's not ABS. I know the feeling of ABS. It's different. You also hear the noise of the tires when ABS has been activated. Besides, it happens under light to medium braking at high speeds. I think it's almost impossible for ABS to activate under that conditions, except if someone drives on ice or oil or something. And if I haven't mentioned, vibration can be felt through the chassis too, especially when brakes are hot and the phenomenon is considerably worse. It can be felt by a passenger too.
 
Originally Posted By: inquirer
Quick question about brake vibration.

I get pedal brake vibration when braking, which can be felt through the brake pedal, but not the steering wheel.

The thing is that the vibration is much worse when the brakes are hot, e.g. after spirited downhill driving and less noticeable during normal driving.

I had issues with brake vibration a few years ago. Different rotors back then. But also different symptoms. Last time the shake was also felt through the steering wheel and got worse as time passed. But it wasn't affected by the temperature.

I understand that vibration that is felt through the pedal and the chassis points to rear rotors' issues. But what does the increasing vibration with higher temperatures mean?


Your rear rotors are warped. It is normal for the vibration to get worse as the brakes heat up.
 
@mightymousetech

My guess is that there is a problem with rear rotors too.

About disc wrapping I read different stories from rotors' manufacturers. For example read STOPTECH's article here:
http://www.stoptech.com/technical-support/technical-white-papers/-warped-brake-disc-and-other-myths
In a few words, the article says that vibration from actual disc wrapping is extremely rare, close to 0. It lists friction material from overheated pads to the disc as number 1 cause.

Here EBC:
https://ebcbrakes.com/articles/pro-cut-lathe/
claims that Disc Thickness Variation, that is a result of but geometry of the disc during installation, is the main cause of vibration.
 
Originally Posted By: inquirer
@mightymousetech

My guess is that there is a problem with rear rotors too.

About disc wrapping I read different stories from rotors' manufacturers. For example read STOPTECH's article here:
http://www.stoptech.com/technical-support/technical-white-papers/-warped-brake-disc-and-other-myths
In a few words, the article says that vibration from actual disc wrapping is extremely rare, close to 0. It lists friction material from overheated pads to the disc as number 1 cause.

Here EBC:
https://ebcbrakes.com/articles/pro-cut-lathe/
claims that Disc Thickness Variation, that is a result of but geometry of the disc during installation, is the main cause of vibration.


As a pro tech, it is not rare at all, I see it almost daily. And no, it is not pad deposits, you can measure the runout (or warp) of the rotor, hot or cold.

If the vibration is felt through the floor, but not the wheel, it is the rear rotors. Once they get hot, it will feel worse, and you probably hear the pads creaking as they move back and forth following the warped rotor when braking at low speed.
 
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Brake rotor warping is very rare. Most brake vibrations can be attributed to run out. When you changed rotors did you clean the hub surface with a wire brush? Most people and quickie brake places don't. Try this before you go throwing $$$ at the problem. Take off the rotors, and clean the hub with a wire brush (I use a bronze brush on a cordless drill) until the surface is completely free of rust, do the same on the inside of the rotor hat. clean the rotor surface on both sides with an aggressive scotch brite pad, perpendicular to the rotor (don't go in circles) spray everything down with brake cleaner (cleanliness is key with brakes) apply a very thin coat of anti seize to the hub to prevent rust in the future. If you have a dial indicator check for run out in 3 o more places with the rotor on the hub and verify spec in the service manual. Reassemble and go for a test drive. It is also VERY important to bed in the pads per the manufacturers instructions for each pad. Different pads have different bedding steps. try these steps first and see if you notice a difference. I have had vibration issues in the past with both factory replacement pads and rotors and high end aftermarket, after I started doing this method of cleaning the hub I have yet to get ANY vibration or noise on my brakes, and a 4000 lb GTO is very hard on brakes especially on curvy mountain roads.
 
Originally Posted By: Gimpy1
Brake rotor warping is very rare. Most brake vibrations can be attributed to run out. When you changed rotors did you clean the hub surface with a wire brush? Most people and quickie brake places don't. Try this before you go throwing $$$ at the problem. Take off the rotors, and clean the hub with a wire brush (I use a bronze brush on a cordless drill) until the surface is completely free of rust, do the same on the inside of the rotor hat. clean the rotor surface on both sides with an aggressive scotch brite pad, perpendicular to the rotor (don't go in circles) spray everything down with brake cleaner (cleanliness is key with brakes) apply a very thin coat of anti seize to the hub to prevent rust in the future. If you have a dial indicator check for run out in 3 o more places with the rotor on the hub and verify spec in the service manual. Reassemble and go for a test drive. It is also VERY important to bed in the pads per the manufacturers instructions for each pad. Different pads have different bedding steps. try these steps first and see if you notice a difference. I have had vibration issues in the past with both factory replacement pads and rotors and high end aftermarket, after I started doing this method of cleaning the hub I have yet to get ANY vibration or noise on my brakes, and a 4000 lb GTO is very hard on brakes especially on curvy mountain roads.


I don't remember what the garage did. It's been about 4-5 years now. Rotors have been driven for about 40k miles now.
I know what you are talking about:
https://www.youtube.com/watch?v=uJg0OC7ZHDU
But I guess if there is excessive run-out the disc gets damaged and the result is called disc thickness variation. I don't think that this is reversible by just cleaning the hub and the rotor's hat and then just reinstalling the rotor.

I have talked with the garage and if I end up changing rotors, then I will make sure all the procedures will be followed and that run-out will be measured during installation.

I also drive on mountain roads often and during downhill sections with harsh repeated braking brakes get too hot. But I just got brake vibration recently.

I generally follow bed in instructions.
 
Sounds like you need a complete brake job. Warped rotors are common and I've seen a lot throughout the years. I've also seen rust buildup on the wheel hub pushing the rotor out and not the kind of rusting in the Northeast U.S.A. but here in Hawaii from sea water.
 
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