Originally Posted by chlemaire
I have now had the new M-Performance brakes serviced twice at 2 different service locations of the very reputable BMW dealer in my area. The dealer is top notch, and I have been a satisfied customer there since 1996.
Well, the brake pedal still feels frustratingly spongy and unresponsive on these so-called 'Performance' brakes. The dealer said they have re-bled the entire system and performed all the required mechanical and electronic work. They said the somewhat delayed/soft pedal feel may be due to the fact that the pistons are larger and require more brake fluid displacement than the stock brakes.
As much as I love the looks of these M-Performance brakes, needless to say that I am hugely disappointed in what I perceive to be almost a degradation in braking responsiveness and performance. This may be a matter of personal preference and judgement is somewhat subjective. Most people would probably find nothing wrong with my new brakes. But I drive a BMW, "The Ultimate Driving Machine" because I enjoy and expect a responsive, dynamic experience at all levels. I expect feedback from the car on everything to be direct, precise, and tight. It has been my experience with my 2 previous BMW cars (1997 528i, 2006 330i), both purchased new. I love everything about my new 335i M-Sport Line, but I can't believe that these newly installed M-Performance brakes can't deliver a better pedal feel!
I would love to hear about the experience of other members who have done the same upgrade.
I have had them on the car since delivery, which is about 3000 miles now. They were definitely spongy at first. After beating on them since break in was complete at 1200 miles, they feel much better but not bbk great in terms of pedal stiffness. So I bought some Challenge Stainless Steel brake lines to go with it. The lines will give you that firmer pedal feel you are after. I'm installing them in the next couple weeks or so and will definietly post an update.
My only other complaint would be the unholy amount of break dust these things produce. Didn't think it was possible to make so much dust lol...