A hydraulic power brake system (1) of a wheeled vehicle or for a vehicle unit has a main brake line (20, 21), in which a setpoint brake pressure can be controlled via a brake valve (4) that is operated via a brake pedal (7), and from which an axle brake line or a wheel brake line (46, 49, 50) branches off. Inlet valves and outlet valves and a pilot control valve of the ABS control system for the vehicle unit or for each vehicle axle are respectively disposed together in an ABS modulator block (69), which also includes a temperature sensor (70, 71, 72) for detecting the oil temperature (T) and a heating element (73, 74, 75) for locally heating the hydraulic oil are disposed in each ABS modulator block (69).