How does a “surge” actuator work?

A “surge” actuator is a crucial component in trailer braking systems, especially for trailers designed to carry heavy loads. Here’s how it works:

• Trailer Braking System Requirements:
  • Trailers designed to carry 3,000 pounds or more must have a working braking system.
  • The neck of the trailer is divided into two pieces:
    • The front side with the hitch.
    • The back half where the master cylinder for the trailer brake is mounted.
  • The master cylinder has a rod extending to the front half of the neck, which helps distribute the weight between the two parts as the load gets heavier.
  • The master cylinder piston increases fluid pressure in the brake lines, sending pressurized brake fluid to each brake drum/rotor through individual brake lines.
• Surge Actuator Mechanics:
  • The actuator operates by the “surge” or “push” of the trailer toward the tow vehicle during braking.
  • This surge causes the actuator to telescope together, applying force to the master cylinder.
  • The master cylinder then supplies hydraulic pressure to the brakes, synchronizing the trailer brakes with the tow vehicle’s axle brakes.
  • A built-in, sealed, and independent dampening shock absorber controls the telescoping action, ensuring smooth and controlled braking.

When the trailer pushes against the tow vehicle during braking, the surge actuator compresses, activating the master cylinder and delivering hydraulic pressure to the trailer’s brakes. This process ensures that the trailer brakes are applied in sync with the tow vehicle’s brakes, providing efficient and effective stopping power.