I own a 2005 Mini Cooper that is the best car I have ever owned with one exception. I am having a brake issue that the dealer can’t seem to find. When I brake (either suddenly or, less frequently, just normal braking) I get a grinding sound and the car does not stop. The brakes have been completely looked over according to the dealer. All seems fine although that is not getting my car to stop. Any suggestions. The car has 15k miles on it.
That “grinding sound” is probably the ABS working. You may have a bad wheel sensor. Or, really bad tires. 
Saying that a car is really great except for the fact that the brakes don’t stop the car is sort of like saying that you really like living in a house that is built over a toxic waste dump. Both conditions are potentially dangerous, with the brake problem being a much more imminent danger than the toxic waste.
If the car is no longer under the bumper-to-bumper warranty, then I would suggest that you consult a well-reputed independent mechanic who is known for his brake work. If it is still under the bumper-to-bumper warranty, then you need to bring the Factory Zone Representative into the situation. Essentially, you have to do something other than continuing to take the car to a dealership that is unable or unwilling to rectify this defect.
Allowing this situation to continue is irresponsible, as you are endangering others as well as yourself by driving this car. Please get it fixed yesterday.
Please see my post problem with my cooper as of today they have not been able to fix my cooper. Check lemon law.
Jerry
read my post problem with my cooper. BMW gave me a great deal because they were unable to find out how to fix my cooper. I was told they were not going put the car back on the street. Have your dealer call in the BMW Rep.