Hydraulic trailer brake system

The braking system is used on a trailer for a road vehicle. It has at least one braking cylinder (28) operated via a hydraulic braking valve (10) onboard the tractor vehicle via a trailer braking Line (13). A pressure reservoir (27) is coupled to the braking cylinder and the trailer braking Line and to respective magnetic valves (36,37) between the braking cylinder and the pressure reservoir and between the braking cylinder and the trailer braking Line. The suction side of a hand pump is coupled to the Line section (38) between the latter valves, the first magnetic valve having an emergency manual operating device (55).