Personally, I think much of what passes for "warped" rotors is actually corrosion. That video Tech posted makes me more sure of it. One of the things I learned in chemistry class many years ago was that corrosion actually takes place more rapidly in an area not exposed to air if it is connected to a portion of metal that is exposed to air. You get rust UNDER the paint around a chip in the paint on a metal fender. It has to do with electolysis. Likewise, I believe that if a vehicle is parked for a period of time, the rotors always develop some rusting, but the metal UNDER the brake pads may be rusting faster that the part exposed to air. Tech's video shows a low spot almost exactly the size of a brake pad. A couple of normal stops will wipe off all the surface rust, but the disc will be uneven.
Those other blogs talk about warpage caused by excessive heat, but I have experienced warpage on various vehicles and can assure you, the way I drive, excessive heat had nothing to do with it. Insufficient driving (long periods of being parked) seems much more likely to be the cause.

 

I see you point but U cant tell me that the amount of brake jobs I have done in the past was from cars that have been sitting for long amounts of time. Not around Atlanta. Warped is kinda odd word more like out of round is better term. And I have also seen it several rotors where there are more then one low spot. Some have 4 thousands of an inch and some haft to take off up to 20 thousands of an inch to get then true again.

 

Yes, I do see the "warped" rotor, however my point is that not all rotors that are cut, actually need to be. In my opinion, in my experience, and from what I read, most times the juddering people experience when applying the brakes, is simple a build up of pad material.

Anyway, I will apologize here, and now, for suggesting you were inexperienced in one of my posts you deleted. I do thank you for leaving my links to the rotor warp myth. Just like religion and politics, we will never agree on this warp issue. I am done with this. Thank you and enjoy your day.

 

The point of an argument or debate is to be able to see both sides which now u have. U at first came on preaching all about no such thing as warped rotors. I do change just brake pads on cars I do not always cut rotor or replace the rotors. The first thing u had said was I was a crook and over charging people for something u though was not true. Based off your personal experiences with how ever many cars u own. I on the other hand have done this cutting of warped rotors on many many different cars all walks of life all brands of cars and all different road conditions. Your own car this is all that u might need to do which I can infact see that is your issue. U must also condone that your car is not the only one out there and all are different how they drive who drives them and how they are driven. Rust on rotors is also a thing the part that the pads sit on will rust up over time if not used correct. But will not be the only cause for warped rotors. Science fact what happens to hot metal when cooled off vary quickly?

 

I agree that rapid heating and cooling is likely a source of warped rotors. I have seen a video of a Lincoln LS V-8 running up to high speed and then braking rapidly down to a stop. The video was shot in twilight and you could see the rotors turning red hot. You see that all the time on race cars. I gotta believe that sort of driving will result in warpage. It's just that in my case, I never drive like that. Now that I'm retired, I probably don't drive 5000 miles a year yet I still have gotten warped rotors, and so has my wife, and I doubt her rotors have ever gotten hot enough to boil water.
Given the humidity in Atlanta, I would bet that corrosion is a problem there, like it is in many places. Remember, rotors are just basically bare cast iron. They'll rust if you look sideways at 'em.

 

As you guys pound your chests, you do realize that the OP was 04/2013 ant the guy has never been back on the site.........

 

oh yeah quite aware