Over the years I’ve towed a few trailers with my truck. One thing that always concerned me, particularly when driving through large cities and over mountain passes was how the brakes on my trailer work. Cargo trailers, utility trailers, boat trailers, camper trailers – there are a ton of different trailer types, and it’s important to know how to slow down and stop when towing any kind of trailer.
How do brakes work on a trailer? There are three main types of braking systems that you might find in a trailer: electric, surge, and air brakes. The electric brakes will draw power from the vehicle’s battery, while surge brakes use a release of fluid to bring the wheels of the trailer to a complete stop on the road.
The air braking system in a trailer is very similar to the drum brakes in a car, and use brake shoes on each wheel to slow them down and stop them.
There are a few varieties of trailer braking systems, all of which will be discussed in detail in this article. If you are curious to find out how the process of braking works in a trailer, keep reading for an outlined description of each variation.
When it comes to maneuvering any kind of trailer on the back of your vehicle, you will need to be able to have control of the movements of both. This is achieved by using the individual braking systems between both your car and trailer.
How Brakes Work On a Trailer
Before discussing the topic of how trailer brakes work, it is important to understand that there are three different types of braking systems that could be found in the trailer in question. These three types of brakes are electric, surge, and air brakes.
In this section, we will be diving into the topics of how each of these braking systems work. Take a look at all of the lists down below to find an organized breakdown of the characteristics of each variation, as well as a step by step process of how they work to bring the wheels of the trailer to a complete stop as you are driving.
Electric Brakes:
- Draw power from the vehicle’s battery
- Use magnetic force to stop the wheels
- Simple lever system within the brakes using electromagnet
- Brake shoes are attracted magnetically
- Most similar to drum brakes in a car
Electric brakes are some of the most common trailer brakes that you can find. They are able to stop the wheels by drawing power from the vehicles battery. These types of brakes will use magnetic force to bring the wheels to a stop in their tracks.
More specifically, this is achieved by the use of a simple lever system inside of the brakes themselves, and requires the power of an electromagnet within them.
The magnet inside of the braking system will attract the brake shoes, motivating them to apply pressure to the inner components, directly transferring it to the wheels of the trailer.
This type of trailer braking system, being the most common choice for most trailers, is also very similar to the drum braking system in a car. More details on these similarities will be discussed within the next section.
Surge Brakes:
- Hydraulic surge brakes
- Master cylinder releases fluid and moves in order to stop the wheels
Surge brakes, also known as hydraulic surge brakes, are great for trailer systems that need to be submerged in water without incurring any damage. So, if you have a boat that you are taking to the lake and unloading in the water on a regular basis, you will benefit from this system.
Since regular brakes can become rusted and damaged when they come in contact with any kind of moisture, these are specially constructed to combat this type of contact.
This type of system works when a master cylinder releases fluid and moves within the trailer in order to stop the wheels on command as necessary.
Air Brakes:
- Use air pressure to stop the wheels in motion
- Each wheel is controlled by brake shoes
Air braking systems, on the other hand, use pressurized air to stop the wheels in motion. This works through the release of tiny brake shoes across each wheel that apply pressure to the lining of the braking system that is transferred to all four of the tires.
Now that you have gotten a brief overview of what each of these braking systems are comprised of as well as how they work, you will find an easy comparison to another system that you might be more familiar with in the next section.
Electric Trailer Brakes Vs Drum Brakes
When it comes to the braking systems inside of trailers, there are a lot of similarities with the drum brakes that are found in some cars. In general, the majority of cars that you will see on the road in the modern day utilize a disc braking system. These types of brakes are distributed amongst all four wheels of the car, and use a disk shaped rotor to apply pressure to the wheels.
However, there are still some vehicles that are equipped with something called drum brakes. Contrary to the traditional disk braking system, drum brakes are only concerned with the back wheels of the car, instead of all of them.
Since drum brakes are very similar to trailer brakes, specifically the electric type, we will be going over a quick comparison between the two within this section. Take a look at the list below for a brief outline on both of these concepts.
Drum Brakes:
- Consist of a tiny round drum component
- Brake shoes within the drum
When brakes are activated, brake shoes apply pressure to the lining of the drum
The drum pushes against the wheels and brings them to a complete stop
The drum brakes in a car consist of a tiny, round drum shaped component that contains other individual pieces inside of it. The drum is located in the rear of the vehicle, and controls the two tires in the back.
There are two brake shoes within the drum that are released on command when the brake pedal is pushed down by the driver. When the brakes are activated, the brake shoes will apply pressure to the inner lining of the drum.
The drum will then push against the wheels, bringing them to a complete stop in the rear of the vehicle. The other two wheels in the front of the car will follow soon after.
Trailer Brakes (Electric):
- Two brake shoes for each wheel
- Brake shoes distributed amongst all 4 wheels (instead of 2)
- Brake shoes are released to stop the tires
- Use a magnet to bring the vehicle to a stop
The brakes in a trailer, on the other hand, consist of the same kind of process that involves tiny brake shoes being released. However, these brake shoes are distributed across all 4 wheels of the trailer, with two of them partnered with each of the tires.
The brake shoes inside of a trailer system will go through a similar process as the drum brakes in a car, only with the use of an electromagnet inside. When the brake pedal is pushed down by the driver, all of the tiny brake shoes will be pushed into the lining, consequently slowing down the wheels and stopping the entire trailer.
As you can see, there are several main types of braking systems that can be found in a trailer. From air to magnets, they use different components to ultimately achieve the same goal of bringing the vehicle to a complete stop.
