Trailer Braking SystemsIn addition to the various types of trailers, there are several types of trailer braking systems.
Hydraulic Surge BrakesA hydraulic surge system consists of an actuating cylinder that's usually integrated with the trailer tongue assembly. As a vehicle applies its brakes, the "surge" of the trailer towards the decelerating tow vehicle automatically compresses the surge actuator. As the cylinder compresses, force is applied to the master cylinder on the trailer; this, in turn, applies force to each of the braking cylinders.
Proper use of surge brakes is primarily dependent upon the assurance of unrestricted movement between the tongue-mounted main housing and the hitch-mounted surge assembly. (Note: Because of this last requirement, surge brakes are not recommended when using a weight-equalizing hitch. Surge brakes are also more expensive, and usually only justified when you're using several different tow vehicles that would each require an electric brake controller.
Electric BrakesElectric braking systems connect the braking system of the trailer to the braking system of the tow vehicle. This is accomplished by the installation of a cab-controlled braking controller. Activated electrically, the braking force of the trailer is generated using magnets and drum armature plates located within each wheel braking system. Electric brakes are usually preferred over surge brakes because their operation is independent of the braking ability of the tow vehicle. For example, if the brakes go out on the tow vehicle, it's then unable to generate enough deceleration surge to activate the surge brakes. But the driver can manually activate electric brakes, thus allowing the trailer brakes to slow the entire rig. This is the way to go for most applications.