Braking Vibration

2009 CX9 with 9500 miles

My wife's car now has the following symptoms. When increasing speed, car rides great. But when braking when speeds are over 35 MPH, the steering wheel will seriously vibrate. Sometimes its a little vibration and at other times its very severe.
Keep in mind that I rarely drive this car and didn't notice this severe vibration a few weeks back. But I did rotate the rear tires to the front. I'm not clear if perhaps this is my issue, but I think not because there is no vibration on car traveling at any speed.

Any ideas?

Thanks,
Denis

Vibration in the steering wheel when braking usually indicates that the front rotors are warped. Vibration felt in the seat when braking usually indicates that the rear rotors might be warped. I know this because i had it in one car before. Replaced the front rotors and did not make a difference. Replaced the back rotors and it solved the problem. Severity of vibration in felt depends on how hard you're braking and how fast you were going.

nyc1dxo, if you did the rotation yourself you may have made a mistake in over torquing the lugnuts. There are a few forums that list the torque specs for the lugnuts. I prefer to stay in the 90-95 ft-lbs range when torquing.

I hate to say it, but your rotors may be toast. You can take them to someone and have them look at the rotors. Rear Centric rotors are $35-40 ish ea., front rotors are $80 ea. at tire rack. I do not recommend turning them. I personally do not like the factory rotors. IMO why pay to have rotors turned when you can take that cash and buy new. Rotor/brake replacement is not that hard. There are directions in the how to section.

Hope this helps. I have replaced all rotors and brakes myself for my 2007 GT. The stop and go driving here in DC, and the fact that I drive 70 miles of it a days contibuted to my rotor warping and almost complete consumption of my front brakes at 40k miles.

It seems if you don't want to experience rotor warping you might want to move to a retirement comunity in Arizona or something. J/k CX9 SportOwner

The car is only 10 months old with only 10,000 miles. It will have to go to the dealer for warranty service.

Will they replace them for free?

Brake pads and rotors are covered for 1yr/12K miles.
Take it to the dealer.

Yah, guess I didn't pay attention to your milage. Definately take it to the dealer.

Same problem as you

Started to experience barely perceptible shuddering when breaking in my 2009 Mazda CX-9 GT at 7500 miles. After a little over one thousand more miles I heard audible noise. At 8,900 miles I took it in and they said the front pads were completely worn through and they reground my rotors/replaced pads under the 1yr/12 month warranty.

We live in the suburbs of Boston and do not do a lot of hard driving. Really disappointed that these didn't last longer. I would take the advice of other people on these forums and replace with some aftermarket rotors once you blow through your first set.

Interesting.
I still have the original pads after 26K miles.....

ceric said:

Interesting.
I still have the original pads after 26K miles.....

Click to expand...

What kind of driving do you do? Mostly highway, mix, city? Maybe use the tiptronic so that the transmission does the breaking for you?

I feel as though something had to have been wrong with the car. It doesn't make sense to go through pads that fast. We don't drive fast and break hard. I think my last speeding ticket was nine years ago and it's not because I've been lucky. I will update on the new set of pads. It only took ten months for the first set to go so we will see.

Update---


New rotors replaced at no cost. Car stops smooth,..

SF bay area traffic.
Mixed driving.
Last time Mazda dealer checked my brakes, they are still in "good" condition.
I do time the red lights, and follow flow of traffic.

Anybody know if mazda has changed the rotors they use now on the CX-9. This brake vibration appears to be a common problem. My car does it as well. No, the lug nuts were not over torqued unless they were overtorqued at the factory. I'm hesitant to change the rotors with another OEM set if I'll just experience the same issue after 10,000 miles.

ceric said:

SF bay area traffic.
Mixed driving.
Last time Mazda dealer checked my brakes, they are still in "good" condition.
I do time the red lights, and follow flow of traffic.

Click to expand...

I have been more careful about braking and now use the tiptronic to downshift when possible. My wife told me the other day that she found she braked through turns (a lot of those in NE), so that may have been responsible for the early wear of the pads. This in turn would have affected the rotors. So until I get new pads and new rotors take my feedback with a grain of salt.

No such thing as a warped brake rotor

This happens on all makes and models...

Contrary to very popular belief, there is no such thing as a "warped" rotor thick or thin caused by normal use. Even tightening the lug nuts past spec will only cause the rotor to conform to the shape of the wheel assuming it's the stronger element of the two.

Check out this article from a company involved in racing for more detals: http://www.stoptech.com/tech_info/wp...rakedisk.shtml

To summarize, brake judder/shudder is caused by physical changes in the surface of the brake rotor due to heat experienced in normal stop and go driving. The more agressive you are with sudden stops, the faster these changes can occur. Particles of cementite are formed in the surface of the rotor that are harder and result in less friction. Because the particles are not formed uniformly over the surface, you wind up with uneven friction and the characterstic pulsating effect.

Before replacing your rotors or pads, try this procedure known as bedding the brakes (you should also do this for new brake installs):

Locate a long stretch of road several miles long.
During a period of little traffic (late night) on this road, get up to 60 mph and brake medium hard down to below 40 mph, then go back up to 60.
Repeat this process 6 times without stopping. It's important to never stop.
Yes, your brakes will get very hot, stink, and maybe even smoke. They will probably fade too, so be careful. Keep in mind that older brake fluid may boil under these conditions and chemically change. If fade continues, get the fluid replaced.

Once done, drive without braking at speed for at least a minute or two to cool everything off.

What you're trying to do is to burn off the cementite or at least create a uniformity of deposits to eliminate the judder. I have routinely used this procedure on all my vehicles for 20+ years with good results. I have never had to have a rotor turned to eliminate judder though one can understand that shaving off a layer of metal would also get rid of the cementite deposits.

As always your mileage may vary.

In addition, German luxury vehicles use soft steel for rotors.
They are designed to wear out with pads on the same schedule.
You need to replace BOTH pads and rotors together.
With softer steel, the rotors wear off instead of letting the aforementioned cementite accumulated on them. The downside is that you get tons of brake dusts on the wheels,
and need $$$ to replace pads/rotors often. (Have you ever wonder why German vehicles have dirty wheels if the owners are a bit lazy in washing them?)

Not just German vehicles, some domestic and even imports use similar systems. My wife's 2004 Ford Escape works that way. Replace pads and rotors together every 30-35K miles.

Ceric is correct about German cars and their brakes being dusty, but they still can develop judder under city driving conditions. I experienced it with a 7 series BMW, but the bedding procedure took car of it though.

My BMW had the absolute worst brake dust imaginable. I replaced 4 rotors and went to a different brand of pads and solved the problem immediately. The stopping power was not diminished under normal conditions, but it took some research to find pads that both weren't dusty, but would also keep the performance at the same level.

I must admit I now laugh when seeing German cars in the parking lot and their nasty black front wheels. Amazing how other companies can produce performance cars with equal or better braking specs than the fatherland, but do not leave black dust all over their wheels.

Just had my 40,000km service at a Mazda dealership and noticed the brakes slightly pulsating on the trip home. Assumed the wheel balance had not been done correctly. Read this thread and figured my problem may be either overtightened lug nuts or accumulation of uneven brake pad deposits.

So I went out this evening and followed the bedding in procedure for the brakes. Figured if it made no difference, next stop would be to re-tighted all lug nuts.
http://www.stoptech.com/tech_info/wp_warped_brakedisk.shtml
and
http://www.stoptech.com/tech_info/wp_bedinstock.shtml

The bedding in procedure worked a charm! The pulsating is 99% gone. What is left I only noticed on one occassion out of about 12 regular stops. Pretty happy with that outcome!

Cheers,
TTubrag.