What are hydraulic surge brakes?

Hydraulic surge brakes are a totally self-contained tow dolly braking system, requiring no electrical, hydraulic or other connection of brake sensing components to the tow vehicle for automatic operation of the tow dolly brakes. In a hydraulic surge brake system, the inertial differential pressure developed between the tow vehicle and the tow dolly, during the braking process, creates a mechanical pressure which is applied to the push rod of the master cylinder in the hydraulic surge brake coupler. This mechanical pressure is proportional to the difference in pressure between the two vehicles and therefore, the hydraulic output of the brake coupler, and resulting brake operation, is automatic, regulated, and proportional to the amount of braking being applied to the tow vehicle.  more