This is a reverse Lockout Solenoid kit for select Demco brand surge brake actuators, intended to allow your Trailer to reverse without locking up your Hydraulic Disc Brakes. Hydraulic Drum Brakes don't typically have this issue and are usually known as Free Backing because of this.
There are 2 main typed of Reverse lockout solenoids: Normally Closed and Normally Open. Most commonly you will see Normally Open Solenoid Valves, which connect to your Tow Vehicles Reverse Lights, and will then Close the flow of brake pressure when the Tow Vehicle is in Reverse. A Normally Closed Solenoid, like this one, is also known as a Bypass Solenoid, because it connects to your Trailers Brake Lights and the main flow of brake pressure is always blocked by the normally closed Valve, until it receives power from the Tow Vehicles Brake Light. This has a few benefits and drawbacks, the main benefit and allure for this type of Solenoid is that it is more accurate (When your Vehicle Brake, the Valve then Opens and allows the trailer to brake) and it doesn't cause your brakes to lock up when going up or down hill. A Normally Open Solenoid is easier to install, it's a simpler design with fewer parts, but because the Valve is usually open and only closes when the Vehicle's Reverse Lights are on, the Valve cannot tell if you are trying to brake, or if your trailer is inclined and pushing into your vehicle due to gravity, causing the Trailer Brake Actuator to activate, and activating the trailer brakes.
This Reverse Lockout Solenoid comes with everything pictured and is a great alternative to the normal Open Solenoid Valve that comes pre-installed on Most Demco Actuators if you trailer around many hills or slopes. The Demco Bypass Lockout Valve also includes instructions for how to install it to your Demco actuator, and this Valve will fit the Demco Actuator Models DA10 and DA91. The Bypass Kit works by allowing brake fluid to be rerouted back into the master cylinder when your trailer is not in reverse. On a steep incline, for example, the actuator would depress and because the valve is closed, the fluid travels down the alternate brake line back into the master cylinder instead. When the Tow Vehicle is braking, whether on an incline or not, the valve opens and allows the brakes to work as normal.
Features:
- Reverse Lockout Solenoid Bypass Kit
- For Hydraulic Disc Brakes
- Great for Trailing around and on Inclines or steep Hills
- Normally Closed Valve
