Trailer Brakes: Air, Hydraulic, or Electric?

Posted by at 18 May 2014, at 09 : 09 AM

Trailer Brakes: Air, Hydraulic, or Electric?

Your trailer brakes work hard for you. It is important to inspect your brakes regularly to ensure that they are in good working order, especially if you haven’t pulled your trailer in awhile. Your brakes could save your life and the lives of others. Properly working brakes will slow the trailer at the same rate as the towing vehicle.

When you are pulling a trailer, your trailer builds momentum behind you as you are traveling. This momentum will push the tow vehicle beyond its capacity to safely stop. Properly synchronized brakes are essential for towing safety. Always allow more distance when towing a trailer then you would in non-towing situations. A little extra distance can save your life!

The heavier the trailer the more you will need to consider your brakes. It is recommended that you consider brakes on any trailer with a GVWR of more than 2000 pounds. Although electric brakes typically are the most common, here are the three most popular types of brakes available for trailers.

Air Operated Brakes [<- You can read more about it]

Hydraulic Surge Brakes – Boat Trailer Brakes are usually Hydraulic Surge

Electric brakes do not make reliable boat trailer brakes. This is because electric trailer brakes work by an electro magnet that is energized from the tow vehicle’s brake controller. As the magnets mating surface in the brake drum begins to rust, it starts to loose its ability to apply enough force to activate the brakes properly.

Hydraulic surge brakes use the force of forward momentum in the trailer caused by rapid deceleration from the tow vehicle. This causes an actuator in the coupler of the trailer to compress and force fluid via small tubing to the brakes.

Surge brakes are composed of a hydraulic coupler, called an actuator, hydraulic brake tubing and small cylinders located in the backing plate assembly. When the trailer surges or pushes against the towing vehicle during a stop, the actuator telescopes and applies force to a master cylinder, which supplies hydraulic pressure to the small cylinders located in the brake backing plates. The cylinders expand and push the brake shoes outward against the brake drums creating the friction required to stop the wheel spin.

This system is unaffected by rust and corrosion and therefore works very well for boat trailer brakes. It’s only draw back is that since backing up simulates the forward momentum during stopping it can sometimes be difficult to back up, especially up a hill.

12v Electric Brakes – Electric Trailer Brakes

Electric trailer brakes are probably the most widely used form of trailer axle brakes. There simplistic design has proven to be inexpensive yet very reliable. They are typically used in trailers with axles of 10,000 lbs or less.

Electric brakes use an electrical current sent from the tow vehicle to energize a magnet. This magnet attaches to a linkage arm which applies the brakes. The amount of voltage sent from the tow vehicle dictates how much braking is applied.

Electric brake components include a brake controller located in the towing vehicle which is connected to the brake light switch under the brake pedal. When the brake pedal is depressed it sends a signal to the brake controller which then sends a regulated amount of voltage through the trailer light plug to the brakes. The voltage passes through the trailers wiring system and into the magnets located inside of the brake assembly and sticks itself to a flat surface on the brake drum. These magnets, usually one on every wheel, are connected to an arm which provides the leverage required to force the brake shoes outward against the brake drums. This friction is what stops the wheels from spinning.

Electric trailer brake assemblies come in right and left hand versions. Each version is configured so that very little leverage is utilized from the brakes actuating arm as the wheels spin in reverse. This allows for very little brake pressure in reverse making it easier to back up with your trailer.

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