Drum Brake Repair Hardware

Electric brake drum systems use electromagnets to activate the brake shoes against the rotating drum.

When the tow vehicle’s brake pedal is pressed, a signal is sent to the trailer’s brake controller, which energises the magnets.

The magnet’s friction against the drum mechanically forces the brake shoes outward, creating the necessary braking force.

How Electric Brake Magnets and Shoes Work

Unlike standard car brakes that use hydraulics, electric trailer brakes use an electromagnetic system to control the stopping force:

• Activation: An electrical current from the tow vehicle’s brake controller is sent to the electromagnet inside the brake drum assembly when the driver brakes.
• Engagement: The energised magnet is attracted to the rotating inside face of the brake drum. The friction between the magnet and the spinning drum causes the magnet to shift or “grab” the drum surface.
  Actuation: This movement pulls an actuating arm that uses leverage to force the primary and secondary brake shoes outward against the drum’s interior surface. The resulting friction is what slows the trailer.
• Proportional Force: The current sent to the magnets determines how firmly they grip the drum, enabling proportional braking force controlled from the tow vehicle’s cabin.
• Release: When the current is stopped, the return springs pull the shoes and magnet back to their resting position, releasing the brake