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New MKX Pulsating Brakes


MKXfan

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We picked up our 2008 MKX the other day. Love the car. During test drive, the brakes made a grind noise at low speeds. The sales person said that it was due to rust forming on the rotors while it had sat on the lot. That noise has gone, but today noticed a pulsating feel in the steering wheel while applying brakes at 30+ miles an hour. Have just over 100 miles on it now. My guess is that it is the rust still wearing down and the rotors not being completely clean. Any one have any thoughts on this?

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We picked up our 2008 MKX the other day. Love the car. During test drive, the brakes made a grind noise at low speeds. The sales person said that it was due to rust forming on the rotors while it had sat on the lot. That noise has gone, but today noticed a pulsating feel in the steering wheel while applying brakes at 30+ miles an hour. Have just over 100 miles on it now. My guess is that it is the rust still wearing down and the rotors not being completely clean. Any one have any thoughts on this?

 

Hi MKXfan. :D While the "grinding" sound you first heard was likely surface rust on the rotors (as the Salesman stated), that rust would have been gone after the first two or three stops (at the most). And just as an FYI: You will get that surface rust again if your vehicle sits unused for a full day or two, or in very humid wet weather. Just the way it is.

 

However, at this point the pulsating feeling in the steering wheel would not be from rust on the rotors. When you can feel a "pulsating" feeling in the steering wheel during braking that goes away when you are not braking, it is most often a warped front brake rotor or rotors. If you feel the "pulsation" in the brake pedal (or the seat of your pants) but not the steering wheel, it would likely be the rear rotors that are the culprit

 

I would recommend you make a Service Appointment and take your MKX in so the problem can be diagnosed and corrected.

 

Good luck. :beerchug:

Edited by bbf2530
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Hi MKXfan. :D While the "grinding" sound you first heard was likely surface rust on the rotors (as the Salesman stated), that rust would have been gone after the first two or three stops (at the most). And just as an FYI: You will get that surface rust again if your vehicle sits unused for a full day or two, or in very humid wet weather. Just the way it is.

 

However, at this point the pulsating feeling in the steering wheel would not be from rust on the rotors. When you can feel a "pulsating" feeling in the steering wheel during braking that goes away when you are not braking, it is most often a warped front brake rotor or rotors. If you feel the "pulsation" in the brake pedal (or the seat of your pants) but not the steering wheel, it would likely be the rear rotors that are the culprit

 

I would recommend you make a Service Appointment and take your MKX in so the problem can be diagnosed and corrected.

 

Good luck. :beerchug:

 

Sorry bbf but now you are wrong. Rust build up can and does cause a vibration when braking if it has built up for long enough. Sometimes a few very hard stops will clean the rotors, but not always. If that doesn't work then he needs to take it in to the dealer. They may be able to "deglaze" the rotors or they may need to be turned. I have seen this many times with vehicles that sat on the lot in the same position for a long time. Either way the dealer can fix it and it will be free.

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Sorry bbf but now you are wrong. Rust build up can and does cause a vibration when braking if it has built up for long enough. Sometimes a few very hard stops will clean the rotors, but not always. If that doesn't work then he needs to take it in to the dealer. They may be able to "deglaze" the rotors or they may need to be turned. I have seen this many times with vehicles that sat on the lot in the same position for a long time. Either way the dealer can fix it and it will be free.

 

Hi druck. :D And what exactly did I state that was wrong? A vehicle sitting on a Dealers lot will usually not have a build up of surface rust on the rotors that a few stops will not eliminate. Certainly not enough surface rust that it would not have been eliminated after 100 miles of driving.

 

So, discounting outside variables such as his vehicle was sitting in a foot of water on the Dealers lot or all 100 miles on his odometer was highway driving with no brake applications, we both came up with the exact same conclusion: That it was most likely a rotor problem and that MKXfan should make a Service Appointment to have his concern diagnosed and taken care of under Warranty.

 

Seems like both yours and my advice are pretty spot on, other than a possible slight disagreement about the final amount of rust that may/may not be on his rotors. And since neither of us will be able to verify the rust total over the Internet, do we really need to debate how much rust is/is not on MKXfan's rotors? As you certainly know from past experience, we already have enough of those types of members on the forums!

 

So I still luv ya druck! And I will certainly respect you tomorrow too! :yup:

 

Good luck. :beerchug:

Edited by bbf2530
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Hi druck. :D And what exactly did I state that was wrong? A vehicle sitting on a Dealers lot will usually not have a build up of surface rust on the rotors that a few stops will not eliminate. Certainly not enough surface rust that it would not have been eliminated after 100 miles of driving.

 

So, discounting outside variables such as his vehicle was sitting in a foot of water on the Dealers lot or all 100 miles on his odometer was highway driving with no brake applications, we both came up with the exact same conclusion: That it was most likely a rotor problem and that MKXfan should make a Service Appointment to have his concern diagnosed and taken care of under Warranty.

 

Seems like both yours and my advice are pretty spot on, other than a possible slight disagreement about the final amount of rust that may/may not be on his rotors. And since neither of us will be able to verify the rust total over the Internet, do we really need to debate how much rust is/is not on MKXfan's rotors? As you certainly know from past experience, we already have enough of those types of members on the forums!

 

So I still luv ya druck! And I will certainly respect you tomorrow too! :yup:

 

Good luck. :beerchug:

 

Yes you are right to take it in to be checked out. You are wrong that rust cannot cause a vibration. And mild rust will go away after a few stops, but if its built up a while, then the only way to stop the vibration is to either machined the rotors, or take a sanding disc to them. I have seen it many times with cars that sat on our lot for long periods of time. Also, ford will not pay a warranty claim on something like that, it usually gets charged to the new car department and not ford. But like you said they should take it in. And while I may not know how much rust is on the rotors, I can speak from expeirence and not from what the owners manual says. And i'm not trying to be a dick, just trying to help.

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Yes you are right to take it in to be checked out. You are wrong that rust cannot cause a vibration. And mild rust will go away after a few stops, but if its built up a while, then the only way to stop the vibration is to either machined the rotors, or take a sanding disc to them. I have seen it many times with cars that sat on our lot for long periods of time. Also, ford will not pay a warranty claim on something like that, it usually gets charged to the new car department and not ford. But like you said they should take it in. And while I may not know how much rust is on the rotors, I can speak from expeirence and not from what the owners manual says. And i'm not trying to be a dick, just trying to help.

 

Hi druck. :D I never mentioned the Owners Manual in this thread, so not sure what that was about. :headscratch: But nevertheless, since the agreed upon recommendation is for MKXfan to bring his vehicle in for diagnosis and service, let's leave it at that and move on.

 

Hopefully MKXfan will post back with the results of his service visit so others can learn from his experience.

 

Good luck. :beerchug:

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You are wrong that rust cannot cause a vibration. And mild rust will go away after a few stops, but if its built up a while, then the only way to stop the vibration is to either machined the rotors, or take a sanding disc to them.

 

How could that much rust build up in just 100 miles? I think it would have to sit for weeks in humid weather.

 

Before taking it to the dealer - try a few hard stops from 50 mph or so.

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How could that much rust build up in just 100 miles? I think it would have to sit for weeks in humid weather.

 

Before taking it to the dealer - try a few hard stops from 50 mph or so.

 

 

Its not that it buildt up in 100 miles, its that it buildt up sitting on the dealers lot.

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Sorry bbf but now you are wrong. Rust build up can and does cause a vibration when braking if it has built up for long enough. Sometimes a few very hard stops will clean the rotors, but not always. If that doesn't work then he needs to take it in to the dealer. They may be able to "deglaze" the rotors or they may need to be turned. I have seen this many times with vehicles that sat on the lot in the same position for a long time. Either way the dealer can fix it and it will be free.

 

Turn the rotors on a car with 100 miles on it. That would not happen if it was my car. It would be new rotor time. By the way, my 2009 Edge brakes grind every morning for the first touch. Then the rust is gone. What is different on this vehicle from others?

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I'll be bringing it in on Saturday to have them look at the brakes. There is still some pulsating when braking at higher speeds, but there is still a slight grinding sound when going a couple miles an hour and braking. Something is going on with the rotors is my guess. Will know more on Saturday. We'll keep you posted.

 

P.S. - other than that, we love our MKX!

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Nacraman,

 

How many miles do you have on your edge? What would be the concern of the dealer turning the rotors?

 

HiMKXfan. :D I will try to give you the short version. There are only so may times (usually twice at most) rotors can be turned before they are too thin (below spec) and have to be replaced. Also, the thinner a rotor is, the more likely it may warp again (usually from excessive heat)

 

Therefore, if the Dealer has to turn the rotors to fix your problem, it is essentially shortening the life of the rotors and making it that much sooner that you will need to have new rotors installed. And next time it may be likely out of Warranty and come out of your pocket.

 

So, if it is a rotor problem and the Dealer says they need to be turned, I would ask if they can be replaced instead. Keep in mind that Ford/the Dealer do not have to replace the rotors. According to the Warranty provisions of a new car, to fix (turn) or replace is completely up to Fords discretion. But it does not hurt to ask. Let's hope the fix is something simple.

 

Good luck. :beerchug:

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I would definitely keep driving and NOT bring the car in for service if it were me. I had my Focus sit for 6 months once and it took a good two weeks of driving before the brakes became vibration free, but they did on there own (still have original pads and rotors on that car, 6 years, 48000 miles). I recently drove a couple vehicles that had sat outside through the holidays and both had significant brake vibration at first that has significantly improved, but not completely gone away yet.

 

If you bring it in you run the risk of the dealer turning the rotors, which as bbf states does reduced their life and increases the chance of this happening again.

 

What's the build date on the MKX? You can find it on the certification sticker on the driver's door jam.

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Brought our MKX in to have the brakes looked at. I let them know I was not a big fan of them turning the rotors at 250 miles. After the mechanic looked them over, he suggested that we keep riding on them and felt confident that they would start responding as normal. As mentioned above they have gotten a lot better since earlier in the week.

 

Thanks for the feedback. Much appreciated.

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You are on the correct path to correct the concern. Warped rotors are another issue.

 

If you perform a hard stop from highway speeds and hold the brake pads against the rotor, you can warp your rotors. Why? - because you can build up to 1,400 degrees from the friction between the pad and rotor. If you permit the rest of the rotor to cool while holding the heat beneath the pad, this will encourage warping.

 

So, what do you do? - After a hard stop, roll the heat out of the rotor by inching forward to prevent the pads from holding heat on one spot on the rotor. This may require you to come to a stop 8 to 10 feet before you actually run out of forward motion room. (One tire rotation will take about 8 feet).

 

Alternatively, put the vehicle in park and let off on the brake if you have no room to go forward or backward to roll out the heat. Once you learn the technique, you will find yourself leaving room on most stops to roll out the rotor heat. (PS - Pads and rotors will last much longer.) :happy feet: :happy feet:

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Well I guess in the end, the Tech saw exactly what I was talking about. It was rust build up on the rotors. A few hard stops may get rid of it. There was one more option like I had said. He could have deglazed the rotors(basically sand them). That would have gotten rid of the rust and does not involve removing any material. That is what I would have done, and I would have had it charged back to the new car department, as ford would not pay that as a warranty claim.

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Well I guess in the end, the Tech saw exactly what I was talking about. It was rust build up on the rotors. A few hard stops may get rid of it. There was one more option like I had said. He could have deglazed the rotors(basically sand them). That would have gotten rid of the rust and does not involve removing any material. That is what I would have done, and I would have had it charged back to the new car department, as ford would not pay that as a warranty claim.
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