Method for operating to brake gear of a vehicle

A process for operating a brake arrangement of a vehicle comprising the steps of:

• (a) providing an electrically controllable service brake system which is operable to generate brake forces independently of driver actuation by urging a service brake piston and fiction lining against a brake disc, and an electrically controllable parking brake system, which is operable to generate brake forces and maintain these forces, the electric parking bake system including an electric motor and gear unit that function in the manner of a nut and spindle arrangement to urge the service brake piston and friction lining toward the brake disc;
• (b) initially actuating the electric parking brake system;
• (c) determining during the initial activation of the electric parking brake system is activated, whether or not the parking brake system has to maintain brake forces for holding the vehicle stationary which are greater than the brake forces the parking brake is able to generate itself;
• (d) activating the service brake system during the initial activation of the electric parking brake system upon determining that the brake forces needed to hold the vehicle stationary are greater than the brake forces the parking brake is able to generate itself, to generate the additionally required brake forces by further urging said service brake piston and fiction lining against a brake disc with the service brake system;
• and
• (e) maintaining the brake forces generated as a whole by both the parking brake system and service brake system with only the parking brake system by advancing the nut and spindle arrangement with the electric motor to hold the further urging of the service brake piston and fiction lining against the brake disc.