The pistons of the master cylinder create brake fluid pressure, which is transmitted further through pipelines and hoses to the wheel cylinders. The master cylinder may be leaking. In this case, the brake pedal, when pressed hard, will «fall through». In addition, leakage can be determined by the wet surface of the brake booster at the bottom of the master cylinder attachment point. In these cases, the cylinder needs to be replaced.
On all modifications, a dual master brake cylinder is installed, equipped with a double reservoir of brake fluid (with one filler plug) to supply both brake circuits of the system. There is a brake fluid level warning light in the instrument cluster.