Abstract: To provide for non-powered evacuation and filling of an anti-lock brake system with integrated control units, a check valve is placed between the suction side of the ABS pump (16) and the wheel brake (6). The check valve (26) enables evacuation and filling of the brake system without energizing electro-magnetically operated, normally closed valves at the place of vehicle assembly. With the check valve (26) in its suggested position, a release of the brake pedal after a brake operation cannot cause trapping of vacuum as previously observed in the pressure relief line as the pressure on the side of the brake line remains above atmospheric pressure and keeps the check valve closed.