One problem related to brake master cylinder has been reported for the 2012 Chevrolet Impala. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2012 Chevrolet Impala based on all problems reported for the 2012 Impala.
When stopped at a red light the peddle would slowly drift towards floor. The car began to roll as if the brakes were releasing. I applied more pressure to the pedal halting the vehicle. I took the car to a dealership and was told it was due to the location of the master cylinder and gm was aware of it. My concern is that this may cause loss of brakeing when in motion.