[Ace555]

Hi all, I’ve had my M340d for nearly 2 years and 43k happy miles.

All of a sudden I’ve started experiencing the brake pedal wobbling under foot as I brake from high speeds (70mph and above). I’m absolutely sure it’s not warped discs and leaning towards it being more of a lower control arm problem. Has anyone else had similar issues? Or had the control arms replaced at fairly low mileage?

Open to any other suggestions on what might have suddenly caused it too.

TIA

[041f0000]

Sounds a bit like a problem I had with my 430i at 10 000 miles. This was “excessive disk runout” and the front disks and pads were swapped under warranty. In my case I also had concentric marks of the front disks which made me initially think the pads were contaminated. I also had a wobble/judder when braking at higher speed.

[Assassin]

If its under warranty get BMW to diagnose/ fix it.

It may be disc runnout, but it can be caused by contamination from the pads causing "grab patches" on the discs. These cars are heavy and hard driving / repeated braking from high speed down to zero generates a lot of heat. If you are then immediately sitting at lights for a while with a foot on the brakes (e.g. motorway exit) it can cook the surface of the pads and cause material to stick to the disc. This then causes wobbling when braking later, usually most noticeable at higher speeds as the heat builds up quicker. I had this problem a couple of time on my previous tuned E60 535d MSport. First time I changes the discs / pads and it went away for a while and then returned. I checked out the controls arms, ball joints etc and they were fine. A mate who does track racing suggested this as the problem and very lightly skimmed the discs for me. Avoiding sitting with a foot on the brakes after really hard driving meant it hadn't happened since.

Or maybe I'm getting old and not driving so hard any more.