Electric/Hydraulic Brake Product Descriptions

Electric over Hydraulic

The electric over hydraulic system is a very adaptable means of supplying robust braking power for a wide range of towing applications. Components of the electric/hydraulic system are mounted on the trailer and consist of an electric/hydraulic power unit, battery, hydraulic lines and hydraulic disc or drum brakes. A 12 volt power supply and electronic signal are supplied from the tow vehicle. The electronic signal is generated by an inertial brake controller of the type typically used with electric trailer brakes.

When the operator applies the tow vehicle service brakes, the tow vehicle controller generates an electronic signal in proportion to the inertia change (slowing) of the tow vehicle. The electric/hydraulic power unit receives this signal and produces hydraulic pressure in proportion to the signal strength. The resulting pressure is distributed throughout the trailer brake system.

Typical applications for electric/hydraulic brake systems range from small single axle utility trailers to large multi-axle recreational vehicles, as well as stock trailers, equipment trailers and flats, receivers, fifth wheel and gooseneck styles. Electric/hydraulic trailer brakes are easily supported by any tow vehicle equipped with an electric brake controller, allowing flexibility in tow vehicle/trailer combinations. Modifications to the tow vehicle are minimal and unobtrusive. Electric/hydraulic brakes are compatible with tow vehicle ABS. The trailer brakes may be applied independently of the tow vehicle brakes. Maximum braking effort is applied to the trailer brakes in the event the trailer becomes uncoupled from the tow vehicle.


The term actuation refers to the device employed to build pressure in the hydraulic portion of the brake system. Several types of actuation are available: Surge, vacuum, air and electric. In the surge brake system the input force to the master cylinder is purely mechanical, in vacuum and air systems the master cylinder is operated through a connecting linkage with a chamber to which air pressure or vacuum is supplied.This mechanical force, generated through direct, vacuum or air power is converted to fluid pressure by the master cylinder assembly, with the pressure being proportional to the input force. In the electric over hydraulic application, fluid pressure is supplied by an electrically operated pump and modulated electronically.