How Electric Brakes Work

Written by Hitchweb Team
Monday, January 7, 2013 — 5 Comments

Take a look at the major parts that make up a brake assembly:

  • Reactor Spring
  • Actuating Arm
  • Shoe Hold-Down Spring
  • Primary Shoe
  • Adjuster
  • Adjuster Spring
  • Magnet
  • Secondary Shoe

Components of an Electric Brake

The large center circle represents the hole through which the trailer spindle goes, so we can install the backing plate on the axle. The 4 smaller holes represent bolt holes which are used to bolt the backing plate onto the Brake Flange which sits behind the spindle.

How does electricity make this brake work? The magnet in the backing plate has 2 conductor wires which tap directly into the trailer wiring. When electricity is on, it magnetizes the brake magnet. The magnet is attracted to the drum face. When it contacts this area, the friction causes it to rotate, which moves the actuating arm, and pushes the shoes out against the drum. Those shoes have a special brake pad material on them that resists the heat caused by that friction. When the shoes press against the inside of the drum, they prevent the hub, and consequently the wheel that's touching the ground from spinning.

How does the electricity get to the trailer brakes? Where does it come from? How do we know which brake to use? Here's how it works: An electrical connection on the trailer plugs into the connector on the vehicle. There are electrical wires running from the trailer connector back to each brake on the axle, as well as to the trailer lights, to create a complete circuit. When the driver steps on the brakes it sends a current to the brake control in the vehicle. The brake control then sends a current back to the trailer to activate the brakes. Here's what that looks like:

How an Electric Brake works


Now that you know how an Electric Brake works, go ahead and browse our selection of TRAILER ELECTRIC  BRAKES




Posted in Trailer Parts


Hitchweb Team
Wednesday, April 15, 2015

Hello Bob, You can just plug it right back in, this will not hurt the trailer. The only reason to replace it is if the pin is or became damaged.

Wednesday, April 15, 2015

While pulling away from my unhooked trailer the emergency wire got caught up and pulled out. I pushed the large plastic pin back into the small rectangular controller on the hitch. Do I have to do anything else to make sure they are not locked up and or will still function when I hook back up to leave the campground.

Tuesday, April 14, 2015

What should I do If the emergency pin on the trailer brakes is pulled out when not attached to the vehicle. Their was no electrical hook up at the time. Is everything the same when I push the large plastic pin back into the little box it came out of? Do I need to do anything special.

Hitchweb Team
Monday, November 25, 2013

Hello Ronald,

That is a very common question. Throughout the U.S. and Canada, there are laws in place regarding towing practices depending on the State or Province. Since most RV's and campers travel over several States and Provinces, it is always safest to go with the average-to-stringent laws as a guideline for any given step. Towing laws can change so make sure to check that the trailer passes the requirements on a yearly basis.

Ronald McDougal
Monday, November 25, 2013

How do I know if my trailer needs to use electric brakes?

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