General description of the braking system (Opel Vectra A)

The brakes operate on all four wheels. The front wheels are equipped with solid or ventilated disc brakes, and the rear wheels are equipped with self-adjusting drum brakes or solid disc brakes (depending on the model). The brake system is hydraulic, actuated by a vacuum booster. The handbrake is actuated by a cable and works only on the rear wheels.

The brake system hydraulic line is divided into two circuits. On models without ABS, the circuits are diagonal, and on models with ABS, the system is divided into front and rear circuits. If one of the hydraulic lines fails, full braking (on two wheels) provided by the second circuit.

The supply of brake fluid to the rear brakes is regulated so that during sudden braking the front brakes are always locked first. The fluid pressure in the hydraulic lines of the rear brakes is regulated by two valves (one for each brake), which are either screwed into the master cylinder or mounted on the rear of the vehicle's underbody (depending on the model).

The direct acting brake booster is installed between the pedal and the master cylinder. The booster is driven by the vacuum created in the intake manifold. If the booster fails, the brakes will still work, but more force will be required to depress the pedal.