Types of Travel Trailer Braking Systemsby Melissa Bajorek
There are essentially two kinds of brakes used for travel trailers: electric brakes and surge brakes. Federal law requires that travel trailers with brakes also have an emergency breakaway system. The weight of a trailer is an important factor for the DMV regulations in each state, and certain states require brakes based on the weight of the tow vehicle. In California, for example, brakes are required on any trailer weighing 1,500 pounds or more, while in New York, trailers weighing 1,000 pounds unladen, or 3,000 pounds when loaded, must have brakes.
According to the California Department of Motor Vehicles, most travel trailers use electric brake systems. Electric trailer brakes are activated via an electrical connection from the trailer to the towing vehicle. Some electric travel trailer brakes use a controller located in the towing vehicle, at the brake pedal. The controller senses pressure applied to the brake pedal by the driver, and then activates the brakes in the trailer. Some models of electric trailer brakes use an inertia switch set into the dash of the towing vehicle. For other electric braking systems, the inertia switch is mounted in the trailer itself. Electric brake systems use magnets to activate the trailer's brakes.
Surge brakes require no electrical connection from the towing vehicle. Surge type travel trailer brakes work hydraulically; using the energy of the towed vehicle to compress fluid in a cylinder and apply brakes. With this type of system, braking is automatic. Usually a surge coupler is found in the tongue of the trailer, which connects to a hydraulic master cylinder. When the driver in the towing vehicle applies the brakes, the momentum of the trailer causes the coupler to put pressure on the master cylinder piston rod as it slides back. The faster the tow vehicle decelerates, the more pressure is applied to the trailer braking system. Once the tow vehicle begins moving forward again, the forward pull on the surge coupler relieves the pressure applied to the hydraulic master cylinder, so the trailer brakes are released. In some states, surge brakes are not legal for heavier trailers. Also, surge brakes get the same input from braking as from backing the tow vehicle. If you plan on using surge brakes, you will also need either a reverse solenoid wired to your reverse lights to release pressure, or a free-backing mechanism designed to release the trailer brakes when the towing vehicle is in reverse.
Breakaway Brake Systems
In the U.S., federal law states that trailers must have breakaway systems that will apply the trailer's brakes if it becomes unhitched from the towing vehicle. For electric braking systems, you'll need an emergency back-up battery system that is used to energize the trailers brakes once disconnected from the vehicle, and a pull pin or breakaway switch. If you choose surge style brakes, a simple cable connected to the towing vehicle can activate the brake system if it becomes unhitched.
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