Understanding Trailer Brakes: Types, Functionality, and Maintenance


Trailer brakes are essential for safe towing, providing the necessary stopping power to manage the additional weight of the trailer and its contents. They are critical for maintaining control and stability, especially during sudden stops or on steep inclines. This article covers the various types of trailer brakes, their functionality, and key maintenance tips.

Types of Trailer Brakes

  1. Electric Trailer Brakes
    • Description: Operate using an electric current supplied by the towing vehicle.
    • Mechanism: The electric signal activates a trailer brakes magnet, which then applies pressure to the brake shoes, causing the trailer to slow down.
    • Uses: Common in a wide range of trailers, from light to heavy-duty applications.
    • Advantages: Adjustable braking force, compatible with brake controllers for more precise braking.
  2. Surge Brakes (Hydraulic Brakes)
    • Description: Use hydraulic pressure generated by the momentum of the trailer pushing against the towing vehicle.
    • Mechanism: When the towing vehicle slows down, the trailer pushes forward, compressing a hydraulic cylinder that activates the brakes.
    • Uses: Often found in boat trailers and rental trailers.
    • Advantages: Self-contained system that does not require an electrical connection, low maintenance.
  3. Electric Over Hydraulic (EOH) Brakes
    • Description: Combine the benefits of electric and hydraulic systems.
    • Mechanism: An electric signal from the towing vehicle’s brake controller activates a hydraulic pump, which then applies pressure to the brake calipers.
    • Uses: Suitable for heavy-duty trailers requiring strong braking power.
    • Advantages: Provides powerful braking, ideal for larger trailers, responsive and adjustable.

Functionality of Trailer Brakes

  • Brake Controllers: Essential for electric and EOH brakes, these devices allow the driver to adjust the braking force applied to the trailer. Modern brake controllers often feature proportional braking, where the trailer brakes mirror the intensity of the towing vehicle’s brakes.
  • Breakaway Systems: Safety mechanisms that automatically apply the trailer brakes if the trailer detaches from the towing vehicle. This prevents runaway trailers and potential accidents.

Maintenance of Trailer Brakes

  1. Regular Inspection
    • Frequency: Before each trip and during routine vehicle maintenance.
    • What to Check: Look for wear and tear on brake shoes, pads, and magnets. Ensure that hydraulic lines are free from leaks and that the wiring for electric brakes is intact.
  2. Cleaning
    • Frequency: Periodically, especially after exposure to dirt, water, or salt.
    • Method: Clean with appropriate brake cleaner to remove dust and debris. Avoid using water or oil-based products that can cause corrosion or reduce braking efficiency.
  3. Adjustment
    • Purpose: Ensures that the brakes engage properly and evenly.
    • How to Perform: Follow the manufacturer’s guidelines for adjusting brake shoes and pads. For electric brakes, ensure that the brake controller settings are correctly calibrated.
  4. Lubrication
    • Frequency: As recommended by the manufacturer.
    • What to Lubricate: Moving parts such as the pivot points and slide mechanisms in drum brakes. Use appropriate grease to avoid attracting dirt and grime.

Safety Considerations

  • Brake Testing: Always test trailer brakes before hitting the road. Perform a brake test in a safe, controlled environment to ensure that the brakes engage smoothly and effectively.
  • Load Distribution: Ensure that the trailer load is evenly distributed to prevent excessive strain on one side of the brakes.
  • Towing Speed: Adhere to recommended towing speeds, as higher speeds can increase the demand on the braking system.
  • Emergency Preparedness: Familiarize yourself with the manual override function on your brake controller, which can be used to apply the trailer brakes independently of the towing vehicle’s brakes in an emergency.


Trailer brakes are a vital component for safe towing, providing the necessary stopping power to manage additional weight. Understanding the types, functionality, and maintenance requirements of trailer brakes can help ensure safe and efficient towing experiences. Regular inspection, proper maintenance, and adherence to safety guidelines are essential for keeping trailer brakes in optimal condition.