steering wheel shakes when braking

[azturbo3d]

Ever since I got new tires I noticed that my steering wheel shakes when I brake from higher speeds. It's noticeable when I'm getting off the freeway and need to slow down.

Since I've had the tires for about 3k miles now, I'm guessing it's the alignment. However, my steering is dead on when I'm driving normally. Would I need to get that checked or could it be the brakes? At 35k I'm still on the original brakes.

Just looking to see if I can diagnose this problem without driving all the way to the dealership.

 

[Aricjm15]

99% positive it is warped brake rotors. If it were the tires or the way they were balanced it would vibrate all the time while driving at speed.

 

[sumthaiguy]

warped rotors

 

[bigdaddy]

rotors. This happened with my sister's mazda 6 and they had to replace the rotors.

 

[Nliiitend1]

...or more accurately, you have unevenly transferred friction material on your rotors' surfaces.

http://www.stoptech.com/tech_info/wp_warped_brakedisk.shtml

 

[LovinMyMS3]

...or more accurately, you have unevenly transferred friction material on your rotors' surfaces.

http://www.stoptech.com/tech_info/wp_warped_brakedisk.shtml

Maybe more accurately to you. Sorry but I've argued over that to many times to do it again. Rotors warp, plain and simple, you can't measure significant runout with just friction material. Follow your stoptech god blindly, I'll go with my 30 years experience.

 

[sephiroth]

You should be doing the pads also on said rotor replacement FYI, and not say, just replacing the rotors.

 

[nynhex]

warped rotors

+1

Almost guaranteed to be that. That's happened to me on a few other cars. If that's the case I'd suggest getting a nice set of slotted rotors and some hawk pads while you have the brake system unbuttoned. Braided lines wouldn't hurt either

 

[Aricjm15]

Also DO NOT have the rotors turned/milled/whatever. Buy new rotors. I personally feel that it is not safe and 9/10 times the rotor will become warped again.

 

[sephiroth]

Also DO NOT have the rotors turned/milled/whatever. Buy new rotors. I personally feel that it is not safe and 9/10 times the rotor will become warped again.

It's perfectly safe... I'm not sure where you get your information that it will result in them becomming warped again either, but that's false. The only reason it's not in practice like it was 20 years ago is because buying new rotors is so cheap these days. Infact the very manufacturing process of new rotors is almost the same method as turning used ones.

 

[LovinMyMS3]

Also DO NOT have the rotors turned/milled/whatever. Buy new rotors. I personally feel that it is not safe and 9/10 times the rotor will become warped again.

There isn't a problem with turning rotors/drums as long as they are within specs. It is true though, if you warped them once they will warp quicker when thinner since the heat is even harder to dissipate.

 

[sephiroth]

There isn't a problem with turning rotors/drums as long as they are within specs. It is true though, if you warped them once they will warp quicker when thinner since the heat is even harder to dissipate.

true.. but turning drums/rotors usually only removes only fractions of an inch. As long as you're within the wear indicators however, it's not really an issue unless you frequently practice hard braking.

 

[Nliiitend1]

Maybe more accurately to you. Sorry but I've argued over that to many times to do it again. Rotors warp, plain and simple, you can't measure significant runout with just friction material. Follow your stoptech god blindly, I'll go with my 30 years experience.

False. You can absolutely measure runout with just the metallurgic changes that unevenly deposited friction material causes. It's been proven using metallurgic analysis coupled with thickness variation data.

No need for you to argue with me.

Yes, rotors can warp. In fact, they will do so quite easily if proper lugnut torquing is not consistently performed, but the pulse that people feel in their brake pedal is usually caused by what the "Stoptech Gods" preach about...

 

[dmention7]

Check the torque on your lugnuts. If it happened after you got new tires, it's possible the tire shop overtorqued the hell out of your lugnuts, which can contribute to rotors warping.

You'd think those places could afford even a $20 menards torque wrench, but it seems to be standard practice to have some gorilla with an 8' breaker bar tightening lug nuts at tire shops.

 

[Mid_Life_Crisis]

Just my two cents on the whole turning rotors issue. I will turn modern rotors once if they have what I consider minor damage, e.g. light scoring, but not for something like warping. Once you have heat damaged a chunk of metal, it is susceptible to it happening again. With the cost of rotors these days, it just isn't worth the headache.

 

[ATXMSP3]

ON hte issue of warped rotors. rotors warp due to several contributing factors. Excessive heat buildup being the leading cause. ALso if the lugs arent tightened up in a "star" pattern it will cause uneven clamping pressure on the hat of the rotr which can lead to warping(kinda like torquing the heads of an engine). Once a rotor is warped it can be machined as long as the runout(warpage) is within factory specs and the machining process doesnt take them below factory specs. This being said, machining a warped rotor will cause an imbalance of metal thickness and once they get REALLY hot they can attempt to rebalance themselves again which will cause them to rewarp. This "rebalancing" that happens is why most mechanic shops recommend replacing rotors that have become warped. If you really want me to get into the technical aspects of this i gladly will so just send a msg and ill respond.

 

[funksilver07]

there you go, all better now. (upyours)

 

[Nliiitend1]

^^Pssst!

Look at post #5 of this thread.

 

[sephiroth]

this is why the internet invented a hyper text link. so we wouldn't have to post entire articles.

 

[funksilver07]

You're welcome...thanks for your internet wisdom.