The combination is known as a dual master cylinder. Ignition was later blamed on spillage from the adjacent master cylinder. Stock master cylinder must be used. The replacement of the master cylinder costs about 500 euros. The back-up system consists of an electric motor which supplies pressure to the master cylinder. The pressure inside of the master cylinder is created by a primary and secondary piston. This, in turn, pushes the diaphragm toward the master cylinder. Brakes were now upgraded to a safer split system including a dual reservoir master cylinder. The master cylinder was located beneath the driver. The brake calipers, rotors and master cylinder were unique to the M3 model. Fitting a larger master cylinder can also overcome the excess travel. A smaller diameter master cylinder has the opposite effect. The hydraulic system gained a separate master cylinder for the clutch. The calipers are now Brembo M50 Monoblock and the master cylinder is a radial Brembo. The cylinder that the operator uses is called the master cylinder.