I have this vibration in my 2004 530i since early 2016 whenever I stepped on brake pad at speed faster than 40 mph. Vibration is kind of from "all" sides meaning, brake pedal, steering wheel. There is no vibration when braking at speed less than 40 mph.

Front brake rotors were replaced about 20k miles ago, front brake pads were replaced about 10k miles ago, rear brake rotors and rear brake pads were replaced less than 20k miles ago. Car has about 120k miles now.

Any suggestion to troubleshoot this braking vibration issue ?

Thanks,

Ching-Ho Cheng

 

Measure the runout of the hubs and rotors. If they are more than .002" out then you will probably feel it.

 

Thank you for the response. How do I measure the runout between hubs and rotors ?

 

There could be a couple of factors contributing to your problem. The first thing I would ask is how come only your front rotors were replaced and not both rotors and pads. Pads can be installed without installing new rotors if the rotors are still in good condition but, old pads should never be reused with new rotors. Reason behind that is because pads "bed" to the rotors and match the contour of the rotor. this is very important so that hot spots don't form and create warping. A new set of pads on a new rotor will seat or bed uniformly and provide even friction distribution between the rotor and pad mating surfaces.

In short if you have replaced the rotors with and utilized the old pads, that is most likely your problem.

Other things to to think about is driving style. Do you ride your brakes a lot? Riding your brakes is the most common reason for warped brakes do to the fact that the inability for the brake rotor to cool.

Unfortunately either way it sounds like you need to replace your rotors and pads regardless. I would start with the fronts considering you feel vibration in the steering wheel. Hope this helps.

 

Thank you for your explanation. I did not replace pad because it was not too "long" mileage wise. I will replace both rotors and pads again when Spring really arrives in Boston.

 

Did you ever replace your upper control arm bushings ("hydro bushings")? After 120K miles, they might be shot. Grab the control arm and try to twist it, if the bushing is toast it will twist rather easily and feel loose.

 

No, upper control arm and bushings are still the original. I will check them out too. What about lower control arm, would it also contribute to the vibration symptom too ?

Thanks.

 

The lower control arms normally last longer than the upper ones, especially their bushings. Also when braking, the upper control arm bushings take up most of the load, the reason you feel the vibration when they are worn out.

 

Thank you for the explanation.

 

I removed front wheels today and checked on upper control arm. Bushings on both arms (left and right) had rubber separated from the "triangle center piece". Driver side was worst than passenger side; about half way separated. Passenger side was about 1/3 separated.

I ordered new arms from FCPEuro and hopefully could replace them this weekend if weather permits.