Warped Rotors
09-11-18, 06:42 PM
#16
Don't drive like a madman and then jump on the brakes a lot. In other words, leave earlier to give yourself plenty of time to take it easy. You'll be surprised how changing your driving habits from aggressive to easy braking will affect your brakes. Your rotors will run cooler, and last longer, along with your pads. OEM rotors and pads is the way to go. Bell Lexus in Arizona have an ebay store, and they are reasonable. Check them out.
09-11-18, 08:24 PM
#17
Driver School Candidate
Replaced my brakes with new oem pads on what i believe are the original rotors with 164k on them. Started getting moderate vibrations braking 50+ mph. Replaced with oem rotors and now silky smooth again. OEM is the way to go imo
+1 on bell lexus of arizona. Always some of the best prices especially combined with the 20% off ebay coupons that pop up time to time.
+1 on bell lexus of arizona. Always some of the best prices especially combined with the 20% off ebay coupons that pop up time to time.
09-12-18, 09:11 AM
#18
Rookie
Thread Starter
I'm not sure if it's a tomato/tuh matow thing, but I'm of the camp that says rotors do not warp. They become unsmooth or have runout, because something embeds in the pads, or on floating calipers pins bind up, or rotors become scored, etc. So if this happens repeatedly, there could be something in the environment that causes it. On some vehicles, it's a factor as stupid as parking on a stone driveway. my .02
Also, I know that the term "warped rotors" doesn't mean the rotors are literally warped, and that it's deposits left on the rotors from heating the pads up. My wife gets into lots of stop and go traffic, in Florida (hot), and I'm sure that's not helping either.
I'm going to get OEM pads and rotors and hopefully that solves the problem, if not there's obviously something else going on.
09-13-18, 07:17 AM
#20
Rookie
Thread Starter
Well even if Florida's heat doesn't impress you, it's still a hot climate. Combined with heavy stop and go traffic in a 50 mile commute five days a week, that translates to lots of heat going into the brakes. If you're a skeptic and don't want to believe in the concept of warped rotors I don't know what else to you man 
09-13-18, 07:34 AM
#21
Lexus Fanatic
lol did you follow the link to Raybestos tech training? They engineer the brakes and state no such thing. To be clear, nobody is disputing brake pulsation, it happens all the time if the surface becomes unsmooth or has runout. The source is not heat. My front brakes are OE and have almost 29k now, no pulsation. But that is not to say that a person using Centric and Akebono, would expect to have a pulsation at 29k either. The only reason it matters is it's helpful to get to the root cause if one acknowledges what the possible causes are.
edit: one thing I did notice about our rotors. There are not set screws holding them in place. All of mine are free to wobble, as they are only held in place by the pads and calipers. Even my severely rusted cheap aftermarkets that were on the back, simply fell off when the caliper was removed. One would think that it's a little less precise installing a rotor onto a hub in this scenario, especially if the machining of the holes are off (shouldn't be). Personally, I think having a set screw makes sense, and also makes for easier installation and alignment prior to reinstalling the caliper.
edit: one thing I did notice about our rotors. There are not set screws holding them in place. All of mine are free to wobble, as they are only held in place by the pads and calipers. Even my severely rusted cheap aftermarkets that were on the back, simply fell off when the caliper was removed. One would think that it's a little less precise installing a rotor onto a hub in this scenario, especially if the machining of the holes are off (shouldn't be). Personally, I think having a set screw makes sense, and also makes for easier installation and alignment prior to reinstalling the caliper.
Last edited by Johnhav430; 09-13-18 at 07:44 AM.
09-13-18, 08:08 AM
#22
Rookie
Thread Starter
It was just my theory/opinion as to how it happened, still doesn't negate the fact that brake pulsation or "warping" is a thing. If you read the comments below the article you linked, there are a lot of mechanics that disagree with it, and it's clear there are differing opinions as to how it actually happens. But one paragraph in the article did get my attention.....
So basically they are saying ceramic pads are a problem......And I do have ceramic pads on my car.
Also, some quotes from the comments....
[edit] I properly torque the lug nuts so that's not the issue either.
the semi-metallic pad used with police cars will grind away the high spots on either side. On the other hand, the ceramic pad used with retail cars will transfer material to the high spots. In just a few thousand miles, the rotor will have a significant thickness variation, either from worn away rotor or material transfer from the pad. Rotor thickness variation causes brake pedal pulsation and steering wheel vibration!
Also, some quotes from the comments....
I'm a licensed tech And been following the proper procedures for years, but it still doesn't seem to work, we warranty rotors like it's going out of style,. We are beside ourselves, we don't know what to do anymore
Somebody should design a bolt on braking system that eliminates all these issues
Somebody should design a bolt on braking system that eliminates all these issues
I use to work in the industry, I also went to the top college in the nation for automotive technology. I no longer wrench as a mechanic in a professional capacity for good reason.
I don't fully agree with the article, but it is not garbage either. Their is alot of truth in it.
Yes many times improper torque is causing the problem. Most techs will disagree with this because it will cost them time and money to do it correctly. They dont want to hear it. I am totally against torque sticks as well. The best way is to have someone in the vehicle with it raised pressing on the brakes while the other is torquing them to spec following procedure. Yes, its a time consuming two person job.
Unlike this article, you have to go either 2 or 3 times around depending on vehicle, not once. GM even has a service bulletin.
Heat and abuse is also a factor. Don't believe me, read the Chevy HHR forums and see what people are doing to fix their brakes. These are people going the job right and still having the problem and fixing it by using different rotors.
I have fixed brake pulsation issues by using quality rotors and pads. When I say quality, I am not including OEM in that category.
Don't use quality parts = pulsation. Don't do it correctly = pulsation. Harsh driving conditions = pulsation.
Even raybestos has different grades of rotors and pads. And yes their is a difference. So their article contradicts their marketing and real world conditions.
I don't fully agree with the article, but it is not garbage either. Their is alot of truth in it.
Yes many times improper torque is causing the problem. Most techs will disagree with this because it will cost them time and money to do it correctly. They dont want to hear it. I am totally against torque sticks as well. The best way is to have someone in the vehicle with it raised pressing on the brakes while the other is torquing them to spec following procedure. Yes, its a time consuming two person job.
Unlike this article, you have to go either 2 or 3 times around depending on vehicle, not once. GM even has a service bulletin.
Heat and abuse is also a factor. Don't believe me, read the Chevy HHR forums and see what people are doing to fix their brakes. These are people going the job right and still having the problem and fixing it by using different rotors.
I have fixed brake pulsation issues by using quality rotors and pads. When I say quality, I am not including OEM in that category.
Don't use quality parts = pulsation. Don't do it correctly = pulsation. Harsh driving conditions = pulsation.
Even raybestos has different grades of rotors and pads. And yes their is a difference. So their article contradicts their marketing and real world conditions.
[edit] I properly torque the lug nuts so that's not the issue either.
Last edited by leica; 09-13-18 at 08:55 AM.
09-13-18, 08:42 AM
#23
Lexus Fanatic
Just thought of an example....my Maxima's RF had a brake hose go bad internally--caliper would not release. I actually replaced the caliper, and to my surprise, same thing. At times had to use the engine to overpower the brake (or I could wait long enough for the fluid to drain out), and there would be white smoke billowing out of the wheel. Once I corrected the issue, the brakes worked fine. Imagine how hot the pads would have had to have gotten for white smoke to come out? I'm going to respectfully say that fortunately, none of my brake jobs resulted in pulsation later on with various hardware, and that I don't think enough heat can be generated to warp rotors physically. But I am in no way disputing that rotors can have a pulsation and have runout, deposits, scoring, embedding, etc. I actually prefer semi metallic pads as they perform, do not need to warm up, but they dust like a *****! and they are very unkind to rotors, they bite them. Lexus is ceramic but BMW semi metallic.
09-13-18, 12:15 PM
#24
Rookie
Thread Starter
Also in the comments of that article there is a mechanic claiming he got counterfeit Brembo rotors and they warped badly, I got mine off ebay so it's certainly possible I got a very bad quality pair of rotors.
09-13-18, 01:11 PM
#25
Lexus Fanatic
Hopefully new discs will do the trick....I get my Akebono pads from eBay because they are a few bucks cheaper....look authentic lol it did cross my mind what if they aren't....believe me I notice things and quality control is bad all around. Sometimes 2 packs of grease, sometimes one. Sometimes the hardware is in the box differently.
09-13-18, 03:56 PM
#26
Rookie
Thread Starter
What you have to consider as well, is that Raybestos is never going to admit their product is causing a problem, it's easier for them to blame the techs and the procedures they are using. I'm going to give the techs more credit because they are out there in the field dealing with poor quality parts and having to foot the bill. Personally, I'm not going to put my faith in the product's biased engineers telling me it's not the product that's the problem. Like the guy I quoted said, "even raybestos has different grades of rotors and pads. And yes their is a difference. So their article contradicts their marketing and real world conditions."
09-13-18, 08:19 PM
#27
Moderator
Brakes on a car are designed to do one thing - turn the energy of a car's weight and speed into heat. That is how they stop the car. 100% of the car's inertial energy is converted into heat via friction of the brake components. Brake components can reach 350-400F in routine driving and with aggressive "track day" style driving can reach 900-1000F. Heat from aggressive driving, or sticking calipers/pads, most definitely affects rotors either via direct warping of the rotor disc or via brake pad material cooking and adhering to the rotor surface (or both).
Last edited by Jabberwock; 09-14-18 at 06:17 AM.
09-14-18, 05:14 AM
#28
Lexus Fanatic
Put it this way, I stupidly listened to the forum and bedded my OE BMW brakes. The ****** box of pads has the factory recommendation on a hang tag, to go easy on them for 1000km! The tech is supposed to put this on the rearview for the customer.
The rotors changed colors, that's how hot they got after this bedding process. Like hot coals with a bluish tinge. That was 2 yrs ago, and there is no pulsation. If we want to accept that runout and uneven wear is the cause of pulsation, we can, if not, then let's just call it pulsation. I saw a relatively new E63 AMG (not s) at Costco with the rear rotors scored, showed it to my wife, and said what a shame. That's not the factory pads/rotors that caused it, it's the environment in which the vehicle was operated.
If I ever change my rotors and the LS430 is pulsating, that's not something I can live with. The car would get a 2nd set of rotors, if it still did it, car is gone (it's only worth $6k now not like it's $20k or anything).
edit: The reference/benchmark is that so far in 2 yrs./28k, there has never been a pulsation. So if one develops and it cannot be eliminated, something changed. Maybe hub related, maybe not.
The rotors changed colors, that's how hot they got after this bedding process. Like hot coals with a bluish tinge. That was 2 yrs ago, and there is no pulsation. If we want to accept that runout and uneven wear is the cause of pulsation, we can, if not, then let's just call it pulsation. I saw a relatively new E63 AMG (not s) at Costco with the rear rotors scored, showed it to my wife, and said what a shame. That's not the factory pads/rotors that caused it, it's the environment in which the vehicle was operated.
If I ever change my rotors and the LS430 is pulsating, that's not something I can live with. The car would get a 2nd set of rotors, if it still did it, car is gone (it's only worth $6k now not like it's $20k or anything).
edit: The reference/benchmark is that so far in 2 yrs./28k, there has never been a pulsation. So if one develops and it cannot be eliminated, something changed. Maybe hub related, maybe not.
Last edited by Johnhav430; 09-14-18 at 05:18 AM.
09-17-18, 06:51 PM
#29
I put cheap made in China rotors on the front that had about 1/16th runout brand new. They came “pre-warped” from the factory! I was just going to get rid of them but I figured I would just try them out to see if they worked at all. Funny thing is they feel normal. No pulsing, stopping power is good. I guess I’ll leave them on, but I still don’t recommend them. They’ll probably cause something else to wear out. Buy something better.
09-18-18, 01:02 AM
#30
Instructor
It's not usually the heat itself that warps rotors, it's uneven cooling. If you get the brakes hot and keep driving the rotors will cool evenly and they'll be fine. If you get the brakes really hot and then park the car right away you can warp your rotors. The portion of the rotors that stay covered by the brake pads cool at a much slower rate than the rest of the rotor that is exposed to the air. This is what causes them to warp.