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2013 ATS Peformance 3.6 AWD
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I am about ready to drive this car into a lake. My front brakes were pretty much done, they were pulsating. so i replaced the fronts and rears with OEM rotors and pads. First set of front pads and rotors were good for a month and then they started getting major pulsations. Couldnt believe it, got pissed and replaced them again with new OEM rotors and pads. Everything was all good. Now we are 2 months in on the 2nd set of new front rotors and pads and i am starting to get that pulsation again. Plus its hit or miss. I can stop 8 times in a row and no pulsation, 9th and 10th time i get it, then 11th it goes away again. It is speed dependent and not speed dependent. The rotors still look good, the pads look good, calipers seem fine. I will say these dust way more than the factory and I made sure to get the AC delco part number and not the Bosch branded versions that seem to dust more.

Do you think I have a bad caliper, or just bad batch of either rotors or pads as I did buy from the same company? Which aftermarket guys make a decent set of front rotors and pads for not super expensive on these cars.

Its a 2013 3.6 AWD
 

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The wheel hubs probably have some lateral runout. Take the car to a shop with an on car brake lathe and have them cut the rotors on the car. The on car machines compensate for the runout.
 

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You can try indexing the rotors first. I have found that most cars have hub runout greater than .002". So no matter what brand rotor you use, you wind up with some runout which will lead to pulsation and warped rotors.
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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Yup ^ ^ ^

ANY wheel/hub/rotor runout will cause problems. So will incorrect lug nut torque and torque sequence.

Study the various tech articles on brake judder and pulsation in this link and also the tech white papers (and a brake rotor lathe on-the-car) in the EBC website.


 

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2013 Cadillac ATS
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Warped rotors are an urban legend, this does not happen. What happens is brake pad particles get fused into the rotor from high heat and pressure, and can form microscopic bumps on the rotor. The pad hardware could be seizing, not allowing the caliper piston to retract. Disc brake hardware must be replaced and lubed with every brake job. The mounting surfaces that the hardware rides on must be perfectly clean, too.
 

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Warped rotors are an urban legend, this does not happen. What happens is brake pad particles get fused into the rotor from high heat and pressure, and can form microscopic bumps on the rotor. The pad hardware could be seizing, not allowing the caliper piston to retract. Disc brake hardware must be replaced and lubed with every brake job. The mounting surfaces that the hardware rides on must be perfectly clean, too.
Warped rotors are certainly real, and they are the most common cause of brake pulsation. You can easily check for warped rotors with a dial indicator.
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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69,873 Posts
Cast iron brake rotors do not "warp". Which is why they're machined from cast iron, They DO develop out-of-round conditions and pad deposits. Incorrect lug nut torque, hub runout, and dirty/rusty wheel/rotor/hub mounting surfaces also contribute to brake judder.

Good info in this link as well as in the Centric/Stoptech website.


Some shops use an on-the-car brake rotor lathe that trues your rotors on your car on your hubs. About $65 a wheel.
 
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