It seems like every time I replace the rotors and pads on my car, within just a few month's time, there will be a build-up of something in spots on the rotors that causes the steering wheel to shake when the brakes are applied. I don't know what causes it. I clean the rotors with brake cleaner before I install them, is there something else I need to be doing? Is it cheap pads? I don't get it. I think I'm just going to buy a spare set of rotors and when this happens, I'll just replace the rotors, and then have the ones with the build-up on them turned. That way I'll get more use out of them...it would be nice to find out what's causing this build-up...
High spots build-up on brake rotors
- Thread starter grampi
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Maybe following the proper break-in procedure. Check out the brakes below that are from Canada. I think they're cheaper because of the favorable exchange rate. Very good verified reviews for them unlike a lot of the other brakes on Amazon.
Amazon link
Amazon link
Did you clean the hubs flanges and index the rotors? I had that problem and after indexing had to install a shim. Took 3 sets of rotors to discover how to fix the problem. The Critic posted a thread that gives a little info on indexing:
Centric C-TEK 121 Economy Rotors
Centric C-TEK 121 Economy Rotors
So many of today's rotors are of questionable quality. Many are made in China from the lowest quality scrap iron. It's no wonder they warp and have hard spots.
One thing that is said to cause issues is a high intertia complete stop, then remaining on the brake pedal without creeping forward. The heat transfer between pads and rotor can cause a hot spot. I know some claim this is the main reason rotor warp or wear unevenly. It may be a contributing factor, but it's certainly not the only reason rotors warp and become uneven.
I rent cars all the time. It's not unusual for me to warp a set of rotors with some spirited twisty mountain road driving. The Mazda 6 I just turned back in warped the rotors during a downhill run.
I have a lathe and twice now have carefully turned the relatively small diameter front rotors on my 2009 F150 4x4 SuperCrew Lariat 5.4L. Neither time resulted in long lasting smooth brakes. In fact, I'd say they were smooth for about 2000 miles this last time. Replacement with Motorcraft rotors solved the issue. (made in China BTW)
One thing that is said to cause issues is a high intertia complete stop, then remaining on the brake pedal without creeping forward. The heat transfer between pads and rotor can cause a hot spot. I know some claim this is the main reason rotor warp or wear unevenly. It may be a contributing factor, but it's certainly not the only reason rotors warp and become uneven.
I rent cars all the time. It's not unusual for me to warp a set of rotors with some spirited twisty mountain road driving. The Mazda 6 I just turned back in warped the rotors during a downhill run.
I have a lathe and twice now have carefully turned the relatively small diameter front rotors on my 2009 F150 4x4 SuperCrew Lariat 5.4L. Neither time resulted in long lasting smooth brakes. In fact, I'd say they were smooth for about 2000 miles this last time. Replacement with Motorcraft rotors solved the issue. (made in China BTW)
Originally Posted by Cujet
So many of today's rotors are of questionable quality. Many are made in China from the lowest quality scrap iron. It's no wonder they warp and have hard spots.
One thing that is said to cause issues is a high intertia complete stop, then remaining on the brake pedal without creeping forward. The heat transfer between pads and rotor can cause a hot spot. I know some claim this is the main reason rotor warp or wear unevenly. It may be a contributing factor, but it's certainly not the only reason rotors warp and become uneven.
I rent cars all the time. It's not unusual for me to warp a set of rotors with some spirited twisty mountain road driving. The Mazda 6 I just turned back in warped the rotors during a downhill run.
I have a lathe and twice now have carefully turned the relatively small diameter front rotors on my 2009 F150 4x4 SuperCrew Lariat 5.4L. Neither time resulted in long lasting smooth brakes. In fact, I'd say they were smooth for about 2000 miles this last time. Replacement with Motorcraft rotors solved the issue. (made in China BTW)
I have long been told that rotors rarely actually warp, but rather this phenomenon is caused by a build-up on the surface of the rotors. I just don't know what is causing the build-up. I haven't noticed the high spots starting on the rotors I recently installed, but I also didn't replace the pads when I installed these rotors. It only seems to occur when I install new rotors and new pads at the same time. I'm wondering if it's something in the pads when they're new that sticks to the rotors once they're heated up and causes the build-up...
So many of today's rotors are of questionable quality. Many are made in China from the lowest quality scrap iron. It's no wonder they warp and have hard spots.
One thing that is said to cause issues is a high intertia complete stop, then remaining on the brake pedal without creeping forward. The heat transfer between pads and rotor can cause a hot spot. I know some claim this is the main reason rotor warp or wear unevenly. It may be a contributing factor, but it's certainly not the only reason rotors warp and become uneven.
I rent cars all the time. It's not unusual for me to warp a set of rotors with some spirited twisty mountain road driving. The Mazda 6 I just turned back in warped the rotors during a downhill run.
I have a lathe and twice now have carefully turned the relatively small diameter front rotors on my 2009 F150 4x4 SuperCrew Lariat 5.4L. Neither time resulted in long lasting smooth brakes. In fact, I'd say they were smooth for about 2000 miles this last time. Replacement with Motorcraft rotors solved the issue. (made in China BTW)
I have long been told that rotors rarely actually warp, but rather this phenomenon is caused by a build-up on the surface of the rotors. I just don't know what is causing the build-up. I haven't noticed the high spots starting on the rotors I recently installed, but I also didn't replace the pads when I installed these rotors. It only seems to occur when I install new rotors and new pads at the same time. I'm wondering if it's something in the pads when they're new that sticks to the rotors once they're heated up and causes the build-up...
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That would be the organic material and /or resin binder in the brake pads building up on the rotor. Brake cleaner probably won't remove that but light sanding would. Some pads when new have to off gas the organics / resins. Hard braking too soon can contribute to the spots on rotors especially if when stopped pads being really hot remain in 1 spot leaving the film in that spot. When hot and moving some will call the rotor glazed.
Rotors warp more than you think. I have been doing brakes on customers cars for 35 years and have never seen "pad deposits". A shaking steering wheel when braking can be fixed with my brake lathe. And you can see the high and low spots when its turning the rotor.
If every set of new rotors/pads results in a pulsation within several months, there is a problem with rust buildup on your hub flange or wear with your either the wheel bearing or the hub assembly.
Have you measured the lateral runout after installing the new rotors? Excessive runout will cause uneven wear onto the rotors.
Have you measured the lateral runout after installing the new rotors? Excessive runout will cause uneven wear onto the rotors.
So I read somewhere that it is not warping but pad material transferred unevenly to the rotor. I also read its likely from unevenly torqued wheels which is very common. My Mazda had brake shimmy when braking but I started retorqing my wheels when I would have my tires or wheels taken off at discount. Over time my shimmy has gone away.
This did not happen when pads had asbestos. But that is not an option any more and good thing, I do not want to breathe it.
When I get a pulsation I rebed the brakes, 5 stops from 30 to 5, do not stop. Then 10 stops from 60 to 5. Then one good hard stop on a down hill from 80 to 5 followed by cooling. I do live in rural area so it ia easy, you poor folks that live in big cities do not always have the luxury of a deserted area to rebed.
I personally have had good luck with Wagner Thermoquiets,
When I get a pulsation I rebed the brakes, 5 stops from 30 to 5, do not stop. Then 10 stops from 60 to 5. Then one good hard stop on a down hill from 80 to 5 followed by cooling. I do live in rural area so it ia easy, you poor folks that live in big cities do not always have the luxury of a deserted area to rebed.
I personally have had good luck with Wagner Thermoquiets,
Originally Posted by ragtoplvr
This did not happen when pads had asbestos. But that is not an option any more and good thing, I do not want to breathe it.
When I get a pulsation I rebed the brakes, 5 stops from 30 to 5, do not stop. Then 10 stops from 60 to 5. Then one good hard stop on a down hill from 80 to 5 followed by cooling. I do live in rural area so it ia easy, you poor folks that live in big cities do not always have the luxury of a deserted area to rebed.
I personally have had good luck with Wagner Thermoquiets,
I have done this process before and it did absolutely nothing for smoothing out the brakes...
This did not happen when pads had asbestos. But that is not an option any more and good thing, I do not want to breathe it.
When I get a pulsation I rebed the brakes, 5 stops from 30 to 5, do not stop. Then 10 stops from 60 to 5. Then one good hard stop on a down hill from 80 to 5 followed by cooling. I do live in rural area so it ia easy, you poor folks that live in big cities do not always have the luxury of a deserted area to rebed.
I personally have had good luck with Wagner Thermoquiets,
I have done this process before and it did absolutely nothing for smoothing out the brakes...
Originally Posted by grampi
Originally Posted by Cujet
So many of today's rotors are of questionable quality. Many are made in China from the lowest quality scrap iron. It's no wonder they warp and have hard spots.
One thing that is said to cause issues is a high intertia complete stop, then remaining on the brake pedal without creeping forward. The heat transfer between pads and rotor can cause a hot spot. I know some claim this is the main reason rotor warp or wear unevenly. It may be a contributing factor, but it's certainly not the only reason rotors warp and become uneven.
I rent cars all the time. It's not unusual for me to warp a set of rotors with some spirited twisty mountain road driving. The Mazda 6 I just turned back in warped the rotors during a downhill run.
I have a lathe and twice now have carefully turned the relatively small diameter front rotors on my 2009 F150 4x4 SuperCrew Lariat 5.4L. Neither time resulted in long lasting smooth brakes. In fact, I'd say they were smooth for about 2000 miles this last time. Replacement with Motorcraft rotors solved the issue. (made in China BTW)
I have long been told that rotors rarely actually warp, but rather this phenomenon is caused by a build-up on the surface of the rotors. I just don't know what is causing the build-up. I haven't noticed the high spots starting on the rotors I recently installed, but I also didn't replace the pads when I installed these rotors. It only seems to occur when I install new rotors and new pads at the same time. I'm wondering if it's something in the pads when they're new that sticks to the rotors once they're heated up and causes the build-up...
I think the thing about rotors not warping is "internet mechanics" spreading rumors. Now, on the other hand, it could possible runout from your hubs. Make sure you wire brush them and if possible use a dial indicator on them to make sure. That's kind of overkill, though.
Originally Posted by Cujet
So many of today's rotors are of questionable quality. Many are made in China from the lowest quality scrap iron. It's no wonder they warp and have hard spots.
One thing that is said to cause issues is a high intertia complete stop, then remaining on the brake pedal without creeping forward. The heat transfer between pads and rotor can cause a hot spot. I know some claim this is the main reason rotor warp or wear unevenly. It may be a contributing factor, but it's certainly not the only reason rotors warp and become uneven.
I rent cars all the time. It's not unusual for me to warp a set of rotors with some spirited twisty mountain road driving. The Mazda 6 I just turned back in warped the rotors during a downhill run.
I have a lathe and twice now have carefully turned the relatively small diameter front rotors on my 2009 F150 4x4 SuperCrew Lariat 5.4L. Neither time resulted in long lasting smooth brakes. In fact, I'd say they were smooth for about 2000 miles this last time. Replacement with Motorcraft rotors solved the issue. (made in China BTW)
I have long been told that rotors rarely actually warp, but rather this phenomenon is caused by a build-up on the surface of the rotors. I just don't know what is causing the build-up. I haven't noticed the high spots starting on the rotors I recently installed, but I also didn't replace the pads when I installed these rotors. It only seems to occur when I install new rotors and new pads at the same time. I'm wondering if it's something in the pads when they're new that sticks to the rotors once they're heated up and causes the build-up...
I think the thing about rotors not warping is "internet mechanics" spreading rumors. Now, on the other hand, it could possible runout from your hubs. Make sure you wire brush them and if possible use a dial indicator on them to make sure. That's kind of overkill, though.
I bought dial indicator from Harbor Freight and will never replace rotors without indexing. The most expensive rotors I bought from Napa with the painted hats had more runout than the cheap white box Advance rotors which worked great after correcting the runout on passenger front hub.
Here is a great article about brakes and some good discussion concerning rotor "warp" and heat.
http://www.hendonpub.com/resources/article_archive/results/details?id=1787#comments
http://www.hendonpub.com/resources/article_archive/results/details?id=1787#comments
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