All this talk about rotors don't warp and if they did to the point of pulsing a peddle they would be cracked? Up until a few years ago part of my part time gig was cutting rotors & drums, all types including bi-metal aluminum/steel since 1983. They do warp.... Anyone who has ever lathed customers rotors/drums on a machine could see it right away. After machining pulsing went away... Go figure.

Yes some other things do cause "pulsing". My daughters 2003 Impala had an intermittant pulsing-I found the front caliper pin rubber bushing at the tip of the pin had disintergrated and caused the caliper to "shimmy" once and a while. Replaced the bushing (had to buy the dust boots as well just to get the bushings...) and no more shimmy/pulsing.

2 years prior however-pulsing in Impala. Had to replace the rear rotors. Kept the same pads as they were almost new. Pulsing gone....

Warping anyone?

 

RTV/DTV anyone? You just replaced a rotor that had DTV just as you turned rotors with DTV. The thickness varied from wear as DTV may appear to be but is not warp.

Ok Here is one I think we can trust. EBC makes one of the best pads in the world [if installed properly]. There tech staff is one of the worlds best. They not only deal with Street cars but also Race cars [some of the worlds fastestl , Race Motorcycles. Street Motorcycles and yes even bicycles.
here is one of their tech notes that are very well adressed and helpful to those who sometimes think they know what they are doing and still have issues.


http://www.ebcbrakes.com/automotive/pro_cut_lathe.shtml

Below is a direct quote from the EBC site. Please check it out to confirm this is not just my opinion. I did not capitalize ROTORs DO NOT WARP they did I only copies what they had.

Roto Distortion due to DTV/RTV is very commn infact one in seven cars has a steering geometry problem either when new or after nudging a Kerb or hitting a large pothole [very common after road damage from winter]. Uneducated people still say "My rotors are warped", Well the engineering facts are ROTORs DO NOT WARP, they are made of cast iron, they are very tough and can be run to red heat and cooled time after time and they will not distort, we do this day in day out on our dynos in the EBC lab, Thats they the whole world still uses cast iron as a vehicle brake rotor material, there has never been anything to beat it and probably never will be.

This is what EBC says and I can find more MFG's that will state the same. The only part I can add here is that Ceramic is now the top dog but there are only a couple cars that use them on the street and they will not be common for a good while due to cost.

Please anyone who wants the truth please go to the EBC site and read up and learn. There are even many long time mechanics that do not know the truth. ALso check out the other tech info as it is very informitive and useful.

http://www.ebcbrakes.com/automotive_..._flutter.shtml

I think once many of you read up and learn from creditable web sites and other MFG's you will learn Warp has no part of the brake pulse issues.

This is one problem you need to learn the truth on before you will ever solve it. Replacing a rotor is just eliminating the symptom not fixing the issue.

I work in the performance industy and have to deal with many warranty issues. I also see too often many mistakes with carb and cam installs because of old tech tales handed down over the years. Too many people think they know what they are doing and often are way off base. This is all of us as I still have to keep up and brush up on things I have not done in a long time or with new things that have come along and have changed how we do things like the oils have done to cam install and break in. A lot of good mechanics mess up by not keeping up.

Here is a good explanation from Power Stop. This explains some of what can happen in more detail.

The term “warped rotors” is commonly used to describe brake pulsation, but the rotor is not actually warping at high temperature so the term “warped rotors” is not accurate. The primary cause of brake pulsation is from uneven friction deposits on the rotor. As the brakes get hot, friction material from the pad is deposited as a very thin layer on the rotor. If you come to a hot stop and clamp your brakes down, the pad continues to deposit material on one spot. As you continue to use the brakes, this high spot on the rotor will get hotter than other parts of the rotor. When the temperature starts to exceed 1150 F, the crystal lattice structure of the iron can change into a very hard, brittle material called cementite. Your brakes can hit 1100 F or higher coming off a highway ramp with severe deceleration. Hard spots start to form, and it doesn’t wear down like the rest of the rotor. The hot spot nodules will not dissipate heat as well as the neighboring material, so it gets hotter than the rest of the rotor and causes the spot to grow. The result is a permanent high spot that you feel as pulsating brakes. You can try to turn down the rotor, but chances are the nodule is bigger than the cut depth on the lathe. So it is just a matter of time before the pulsation will come back.

 

Ok bookman. I am still going by what I saw....

 

OK Igor. Sometimes what you see is not always what you think.




I too used to think I knew what the problem was till I found out I was wrong and took the MFG's advice. If sharing their info saves someone else from repeated brake issues all the better. There are just so much bad info out there it has made a mess of people trying to solve their brake issues.

 

ok what is it I think I can see but dont, that's a strange drawing.

 

You have never seen this one before? It is a old classic Opitical Illusion.

Is there 3 or is there 2 pins coming out. If you look at bottom end there are three pins but the top end only has 2 two pins.

Things you see are not always as they appear.

I thought about using one of the magic pictures but I was not sure how well it would work on the web. I have found if you have contacts in you can not always see them for some reason. I never could see them till I removed mine. Photos can do some odd things. Google a magic picture sometime they are pretty cool as the picture comes out of some crazy design like magic.

 

Here is a neat short video on EBC brakes. Andy Freeman in the video is the gentleman who taught by tech class I had with EBC.

He is one of the best informed people I have met on brakes. He really knows his stuff and is one of a few in the industry that is accuratly factual and honest about brakes.


Note the brake dyno's. These guys will really cook pads and rotors till they totally fail all the time. They not only test new pads for the market but they also test pads from batches made for quailty control. If they fail they pull the lot.

 

What are you meaning by seating the brakes?

 

Ok, I seen a video of it, Just simply pumping up the brakes when done nice and hard. Never heard anyone using this term before. I take it people arn't doing this after changing their pads. This was just something I have always done.

 

No, that is not what people are referring to. They are referring to the process where they follow a procedure to heat the brakes up and let them cool - and it is done several times to break in the brakes.