Brake shudder

[Irwin]

In one of the past threads I stated I had warped rotors in my brand new rwdr "c" that the dealer replaced before I bought the car

[DZeckhausen]

Originally Posted by DanRealtor

My Q45: 154 mph, heavy car, stock brakes, had "Warped Rotors" on several occasions (also boiled the brake fluid numerous times).

Different brake pads have different failure modes when pushed way beyond their maximum operating temperature (MOT). For example, Pagid Orange race pads will be consumed rapidly when they exceed 1200 degrees F, but they last a long time at temperatures just below that. Other pads are notorious for laying down big blobs of transfer layer ("pad poop") on the rotors, resulting in judder problems. Likely that was the case with your Q45 pads.

Most street pads are not appropriate for heavy track use. The typical street pad has a MOT between 700 and 900 degrees F. The Performance Friction 01 race pads used by many of my customers and top race teams have a MOT of 2,000 degrees F.

Most track pads are not appropriate for street use because they are noisy and dusty until they reach at least 300 to 400 degrees F. Below that temperature, they are very abrasive and tend to chew up rotors. It's clear from the pad discussions on the SRT8 forum that DCX loaded up those Brembo calipers with pads more suited to the track than to the street.

You may find the following article I wrote on judder problems at the track to be interesting: http://www.zeckhausen.com/avoiding_brake_judder.htm

[DZeckhausen]

Originally Posted by Irwin

In one of the past threads I stated I had warped rotors in my brand new rwdr "c" that the dealer replaced before I bought the car

If the car had a judder problem right from the start, it's possible the rotor was manufactured out of tolerance. If the problem developed after driving some number of miles, then it was likely due to uneven pad transfer on the rotors. Had someone bedded the brakes properly, it might not have happened.

[tlim]

after trying the bedding process, it seemed to help my brake shudder at higher speeds for a short time, but did not last long. it seemed under more heat, the shudder comes back. then tried a higher performance brake pad to see if they would leave less deposits on the rotors under heat, but even after bedding, the shudder came back after heated braking. i finally broke down and changed my rotors, and so far they seem to holding off the shudder. it certainly brings the fun back to driving and braking. hard to conclude if the problem was brake deposits on the rotors due to bad pads, or rotors warping, but i have never had this problem (other than rotors wearing to below minimum thickness, and i rarely turn rotors) on any other vehicle i've owned.

[Americano]

That's the problem we've been having with our 300. You feel the brakes shutter & it only gets worse as you brake from higher speeds. I don't think that special pads & special break-ins would cure the problem. Especially since all 4 rotors have been turned & the current/stock pads are fine.

Has anyone else found a remedy for this problem?

[DZeckhausen]

Originally Posted by Americano

That's the problem we've been having with our 300. You feel the brakes shutter & it only gets worse as you brake from higher speeds. I don't think that special pads & special break-ins would cure the problem.

Have you even tried the bedding process? It's not a "special" break-in. It's the normal break-in that's used to obtain optimum performance from any street or track pad, and it very often cures judder problems.

Especially since all 4 rotors have been turned & the current/stock pads are fine.

This may be a problem, since the very act of turning a rotor under the incorrect assumption that it was "warped" often introduces enough runout to cause significant judder that can not be fixed by bedding.

Has anyone else found a remedy for this problem?

Yes. Hundred of people have. It's right here: Instructions for bedding in your brakes

[stevesrt8]

Originally Posted by DZeckhausen

This may be a problem, since the very act of turning a rotor under the incorrect assumption that it was "warped" often introduces enough runout to cause significant judder that can not be fixed by bedding.

And I always wondered why my "nutcase" extreme machinist brother-in-law takes so long to turn a rotor. I've seen him take ten minutes just getting it all clamped down and turning true before he even begins a cut!

[Northern Rider]

As soon as you take ANY MAKE of car to a service department with brake shudder, they always seem to diagnose "warped rotors". They want to replace the rotors and pads. $$$$!

I have rarely ever seen any tech bed in brakes. It takes too much time and they usually don't have the open roads around their shop.

If you want to save money, follow Dave's advice. I run a fleet of vehicles in my business and the "bedding in" procedure has saved us thousands of dollars. It has also put a smile or two on the faces of my drivers.