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I recently bought a 2015 Mazda 3 S Grand Touring (Made In Japan) with 16k miles on it. The car steering and brake pedal vibrate when braking at 50+ speeds. Can't feel any vibrations on passenger side. After some looking around online it appears to be warped rotors are causing this.
The previous owner did change the tires to some really good ones also I'm not sure how the previous owner drove but after just 16k miles how can the rotors warp?
If the OEM parts are bad then I could just have them changed to some after market ones. I don't want to change them and another 16k miles later end up with the same problem.

Could there be any other issue as to why this is caused? The two mechanics I talked to without even checking said warped rotors and recommended to change out the rotors and pads. I don't want to end up with the same problem later because of a different issue.
Any advice on what I should do? are much appreciated.
 

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You can "warp" rotors in one session if you really want to. Get them checked or look at them, if it's bad you will see the pad deposits or uneven wear.
 

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"Warped rotors" is definitely the common term for a pulsating brake pedal, but the rotors are almost never actually warped from what I've read. It's an undeven deposition of pad material onto the rotor surface. Proper lugnut torque seems to be the best way to prevent it. That means fastening your wheels on with a torque wrench and re-checking torque after 100 miles of driving.

Once they're pulsating you can sand the rotors and pads, or have them turned, or replace them.
 

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My opinion is lug torque is kind of a myth. Most people go to shops who likely over torque
Driving habits is the most likely culprit of "warped" rotors
 

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I'm not sure you guys read the above scholarly-quality article... Did you read about conversion of some of the cast iron disk surface to cementite, for example? What about the proper bedding-in procedure?... It's an informative article!
 

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"Scholarly-quality article... " ?

How do you feel about this statement?
As the braking system in [sic] not quite airtight, a significant amount of water can be absorbed from the atmosphere in the course of a year. A 3% water content in brake fluid drops the boiling point as much as 170 degrees F. Brake fluid should be completely replaced annually.
 

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Carroll Smith is a Racing engineer. If you research him you would similarly conclude. If you read that article, in its entirety, I believe you would conclude that much- if not all of what was said has merit.

Unless of course, you too, have similar credentials...
 

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Annual brake fluid replacement though... Otherwise, yeah. Decent info there. Probably is news to some people for sure. No doubt the average schmo buying "performance" brakes for their DD has had problems with deposition induced pulsation. So it's great that a site selling such things can point to an article like that when dealing with return authorization requests.

As for Mr. Smith... he should be downgraded to "was" a racing engineer as of 2003. RIP
 

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I agree that 1 x / year brake fluid changeout is excessive. But 1 x / 2 years seems reasonable. Few practise that.

Having said that, if it IS done, I imagine that caliper piston problems and master cylinder problems are fewer, perhaps by quite a bit.

Also, it bears saying that the clutch master and clutch slave should be included in the flushing.

Yeah, Carroll Smith WAS a Racing Engineer... hehe.
 

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My opinion is lug torque is kind of a myth. Most people go to shops who likely over torque
Driving habits is the most likely culprit of "warped" rotors
This is a very silly thing to believe. Proper torque-to-spec or at least uniformly torqued (be that over or under-torqued) means uniform clamping force is distributed across the lugs. This is absolutely critical to avoid runout, especially on a part of the vehicle which can be subjected to upwards of 2000+ lbs of force at any given time. That's incredibly important to torque down properly.
 

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I mean in the sense people would rather believe someone torqued their wheels wrong than learn/admit their driving habits may not be ideal.
 

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I have had different issues with my old rotors and pads. From a vibration to severely rust on the rotors. This is not an endorsement but 18 months ago I changed to Power stops on my 2015 madza 3 and all my issues have stopped. Plus they are like $142 with pads per axle.
 

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I put power stop rotors and pads on all 4 corners and within 2 months I had SEVERE pulsation from the front brakes. The rotors looked like hot garbage. Rockauto replaced them for free under warranty. The current ones are starting to show signs of pulsation but it hasn't gotten severe yet.

No effing clue, very frustrating.
 

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"Warped rotors" is definitely the common term for a pulsating brake pedal, but the rotors are almost never actually warped from what I've read. It's an undeven deposition of pad material onto the rotor surface. Proper lugnut torque seems to be the best way to prevent it. That means fastening your wheels on with a torque wrench and re-checking torque after 100 miles of driving.

Once they're pulsating you can sand the rotors and pads, or have them turned, or replace them.
Which driving habits cause differential thickness in rotors?
Who said anything about thickness in rotors? You yourself mentioned that it was uneven deposition of pat material onto the rotor surface. This could certainly be due to driving habits.
Uneven torque would be most likely to actually warp rotors, not somehow make them thicker in some areas than others.
 

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Uneven torque would be most likely to actually warp rotors, not somehow make them thicker in some areas than others.
I have serious doubts that torquing two flat surfaces together could cause one to warp as much as is claimed.
The primary reason that new rotors can seem warped is not cleaning the contact faces were before installation. If you leave rust between the rotor and hub the contact faces won't be in complete contact so the rotor won't be aligned with the hub to begin with. Torquing the lugs down when there is something between the rotor and hub can warp the rotor a bit. Clean it thoroughly and you won't have this problem.
 

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Who said anything about thickness in rotors? You yourself mentioned that it was uneven deposition of pat material onto the rotor surface. This could certainly be due to driving habits.
Uneven torque would be most likely to actually warp rotors, not somehow make them thicker in some areas than others.
Differential thickness in the deposits of pad material across the face of the rotor is what I meant to say, but that's a mouthful and I oversimplified the actual description. Nothing is warped, the metal is not bent, the effective thickness of the rotors has been altered due to uneven deposition of pad material upon the face of the rotor. Hope that helps in understanding

What kind of driving habits do you think would cause these issues?
 

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What kind of driving habits do you think would cause these issues?
Driving habits that would cause this are mostly related to getting the pads too hot-
Braking too hard too often, getting the pads hot then stopping without allowing the brakes to cool sufficiently enough to prevent pad material transfer, and driving with one foot on the pedal all the time, constantly applying the brakes even if not needed are a couple common bad habits.
Are the front brakes dragging a bit? If they are and the pads are getting hot, when you stop there will be material transfer at the spot on the rotor where the pads are. In time this spot will increase as more material is added and the rotor will seem to be warped.
Proper bedding of new pads is important also. This can help prevent uneven deposits and allows the brakes to work more effectively. Sometimes if you have uneven deposits all you need to do is repeat the bedding process, ie do a few successive real hard stops from increasing speeds (30, 40, 50, 60 mph, no full stops and lets the brakes cool by driving normally for a bit before stopping) to remove the old uneven deposits and get a new even layer of pad material on the rotor face.
 
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