So i've had a problem develop on my 2013 R56 JCW which stems back over a year now...

The problem itself is a vibration felt mainly through the pedals / chassis / car itself, and slightly through the steering wheel too, this occurs over a wide speed range but is certainly more noticeable above 75mph. It's Now this translates to a rather obvious vibration / judder through the brake pedal, only when pressing the brake with soft or intermediate pressure, under hard braking I can't feel the vibration much at all.

So far i've done the following in an attempt to cure the problem :

1) Replace all brake discs and pads as the initial thought was warped discs
2) Replace all tyres (michelin PS4s now), in case one tyre had a slight bulge in due to pothole damage
3) All wheels / tyres balanced in case of it being caused by an imbalance
4) Brake fluid changed - during this, I was told that the passenger side front calipers bleed nipple thread has been crossthreaded / stripped at some point in the past, so they couldn't bleed that caliper effectively - could this be causing it?

Also it is in need of tracking but I highly doubt this could cause the above issues.

To finish off, it almost feels as though i'm driving over cobblestones, and this symptom is even at low speeds.

I hope you can help

 

cold or warm make a difference? outside temp and engine temp?
worse at take off vs. highway speed?
do you notice it parked revving the engine slowly?