steering wheel shake when I brake...why?

so when im coming up to the red light and start to brake my steering wheel shakes. Normally you cut the rotors but on bmws you cant. I idk if its something wrong with the rotors or maybe because i have really cheap front tires. any ideas guys?

Bad rotors I would assume. I think it has something to do with uneven transfer of material between pads and rotors, but most call it "warped rotors."

so i just have to changed the rotor? anyway to fix it?

There is a lot of info on this site about it. This was a common problem on early E46's and continues to be a problem for many people (including later models I believe). In fact BMW issued a TSB for the early models - see http://www.revbase.com/BBBMotor/TSb/...dPdf?id=138140. Searching will get you lots more help though.

Also, BMW's aren't special in whether or not you can have the rotors skimmed. If you are far enough above min. thickness, there is no problem having them lathed.

Lue

Step 1: look at rotors.

Inspect first before you start buying stuff. How does the rotor surface look. How are your pads. Should be doing an inspection like this periodically anyway.

It is also most likely your front control arm bushings.

Do you hear a thump when you go over bumps? Sounds like bad front control arm bushings or warped rotors

Yea I hear a bad thump when ever I go over small stuff like sewers. Control arm bushings?

Sounds like thats it. You might need an alignment after you change the bushings out as well.

Good luck !

Bad rotors and brakes, is usually the case.

Controls arm bushings..... Same thing was happening to me before I replaced mine.

Ryan

Originally Posted by chesmari

controls arm bushings..... Same thing was happening to me before i replaced mine.

Ryan

+1

I'd look at control arm bushings first. If they are really bad, you can just grab the control arm and yank back and forth and you'll see and feel it move around like a 1/4" in every direction.

The other trick is have someone watch your front wheels while you drive by them slowly, less than 5mph. When you brake, bad FCABs will cause the front wheels to pop out a bit, it should be pretty noticeable.

as you are hearing from a few, front control arms, and/or the front control arm bushings.
it could be the rotors, wheel bearings or even tires in some instances but the bushings are most likely it.

As has been stated here, there are several things can make the steering wheel shake when braking. Warped Rotors will do it (and if they are not too close to minimum thickness, they can be cut despite what has been said), always install or have your wheels installed without using an air impact wrench and torque all lugs evenly, unevenly torqued lugs is a major factor in warping rotors. Bad Front Lower Control Arm Outer Ball Joints can also cause the problem, as can Front Lower Control Arm Bushings. Ball Joints can be checked by jacking the car up and then moving the wheel/tire up and down (in and out at top and bottom of wheel) feeling for play or having someone move them up and down (in and out at top and bottom) as you look for play at the Outer Ball Joint. To check the Lower Control Arm Bushing, look to see that all the rubber of the bushing is intact and not cracked. While checking these items with car jacked up (and on jack stands, don't work under the car supported only by a jack), also check the Tie Rod Ends for play and the Sway Bar Links and the Inner Ball Joints.

Thanks for all the info guys!!

Originally Posted by Ballinboy1020

so when im coming up to the red light and start to brake my steering wheel shakes. Normally you cut the rotors but on bmws you cant. I idk if its something wrong with the rotors or maybe because i have really cheap front tires. any ideas guys?

Rotors.