I have a 2004 330i ZHP with 79,000 miles. When I apply the brakes at over 20mph there is a very noticeable vibration - but not in the steering wheel. I have Turner cross-drilled rotors and have checked each one to be true and clean. Thinking that the problem still might be with the rotors, I have changed each one in sequence with other rotors and found that the problem does not go away. I changed the control arm bushings about 2,500 miles ago and they appear to be sound. the ball joints look OK but I have not removed the control arms to check them. I am using Hawk intermediate pads that now have about 3,500 miles on them and they still look good. I changed to my winter tires recently and that has not helped. Anyone have any suggestions?
I solved my own problem. The one thing I had not done was change all four rotors at once. Got that done over the weekend and have resolved the problem. While the problem rotors seem fine to the eye, there must be enough of an imperfection to create the vibration. I plan to get the turned and see if that helps.
The Turner rotors were bad but the OEM rotors also have some vibration. I found the Stoptech website to have the best information of the many sites I checked. I am getting the Turner rotors ground and will report back.
I had the rotors turned and they are now fine. The Stoptech website gives lots of detail about brake pad deposits on the rotors. That was definately my problem. When you finish a session at a drivers' school, do not keep you foot on the brakes after you get back to your parking space. The hot rotors and hot pads produce a reaction that will leave a deposit on the rotors. While you cannot see it, it creates the problem I have now experienced with two sets of rotors.
Question about a previous statement you made I have heard it helpful to, after a hot lap, to drive the car at low speed for 5 to 10 minutes to let your brakes cool. Supposedly, the cool air moving over your brakes helps bring down their surface temperature of the rotors? Would this have helped alleviate your issue, or am I talking about something different?
It had to be warping or the deposits you mention. Either way, after a session on the track, one should leave the car in gear and leave the handbrake (and foot brake!) off.
