Quote:
Originally Posted by BimmerRob08
Thanks for posting this info op. I'm going to be specific on the type equipment for sake of this comman issue, not to blame or point fingers at any manufacture. So about 1.5 years ago (18,000) miles ago. I installed an AP BBK New with 12mm spacers. From that day on I have had vibes in the steering at about 80mph range and stronger vibration while braking. About a year ago switched to New ARC-8 wheels, New tires, got rid of the spacers and it never got better. Road force balanced, no hard track days of braking, BMW has checked out the front end. Even did some disc face cleaning with race pads to clean the rotor surface of any pad deposits. Nothing makes a difference. I wish I still had all my OEM parts but don't so can't compare back to stock. Ideas
Thanks.
|
Here's my differential diagnosis for your problem, given that it occurred post BBK install and also under braking:
-imbalanced brake disc (unlikely given AP quality, though still a possibility)
-the AP strap drive system may be faulty or are not aligned properly, such that the disc may be wobbling up and down or side to side relative to the hub. (this is most likely)
What you can do is jack your car up, take your wheel off, get a clothes hanger wire, secure one end to a fixed part of the suspension, and bring the other end as close to the brake disc as possible without touching. Now, retract the brake pads sufficiently to allow the brake disc to spin freely, then spin the disc and watch the surface of the disc relative to the pointed end of the clothes hanger wire. The purpose of the pointed end of the wire is to help you see any wobbling of the disc. If you can see wobbling, then you have found your culprit.
If no wobbling is visible, then I would go to a garage or get a run-out gauge and do the same thing as above, which will provide a measurable reading if there is any brake disc runout. If no significant runout is visible, then I would proceed and have the AP brake discs checked for balance at your brake dealership and any specialist with the right equipment.
I have had wobbling aftermarket floating brake disc issues before in a previous car.