Understanding your trailer brakes is crucial to understanding how to move your trailer safely and securely. Also known as Hydraulic Surge Brakes, surge brakes are extremely common in boat trailers and rental or leisure trailers. Surge brakes are not exactly driver-controlled; they activate automatically whenever the driver slows the tow vehicle.

In the next few minutes, you’ll learn how surge brakes work, why they are the most popular form of trailer brake, and how to maintain them.

Boat Trailers with Surge Brakes

Boat trailers with surge brakes can often be submerged in water when boats are being retrieved and launched, causing premature corrosion on the components of electric brakes. Surge brakes require no setup or knowledge of the braking system to operate, no electric controller or special wiring, and can be submerged in water.

Learn More: Understanding your RV Electrical System

The other types of brakes found in trailers are electric trailer brakes and air brakes. Both of these types of brakes require specialized experience and don’t perform well in water or extremely cold conditions. Surge brakes remove safety hazards in the water and with operators who aren’t familiar with other trailer brake systems. The brakes work like normal for drivers, unless you’re backing up your trailer, and we’ll get to that later.

All trailer brakes have their pros and cons, but surge brakes take the cake when it comes to ease and versatility in the trailer braking world.

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How Surge Brakes Work

When a trailer is designed to carry 3,000 pounds, it must have a working braking system. The neck of a trailer is two pieces. The front side with the hitch is separate and slides on the ledge to the back half of the neck. A master cylinder for the trailer brake is mounted on the back half of the neck and has a rod extending to the front half. When the load gets heavy the rod extends between the two parts of the neck and the weight is distributed between them. The master cylinder piston increases fluid pressure in the brake lines, and pressurized brake fluid flows to each brake drum/rotor through individual brake lines.

Makes sense, right?

What happens when surge brakes are applied?

Trailers with surge breaks typically start to slow when applying the brakes. The momentum pushed the trailer and the trailer load to the front half of the neck and forces it in. Learn the best way to load a trailer here. When the front neck is then pushed into the back, that rod pushes into the master cylinder and then the brakes are applied.

When the tow vehicle moves forward and releases the brakes, the neck extends and releases the surge brakes. The rod can be modified for the brakes to come sooner or later, whatever makes you feel more comfortable.

Related: Choosing the Right Tow Dolly

Backing up a trailer with surge brakes

A trailer with surge brakes needs a special pin to be backed up. The pin is placed in the neck so putting the trailer in reverse does not activate the surge brakes while a driver is backing up or a trailer dolly is guiding the trailer with surge brakes. The pin can be removed when the trailer is ready to travel again.

This is the only tricky part to remember when using a trailer with surge brakes. But, it’s a small price to pay for ease surge brakes give when operating your trailer.

Surge Brake Maintenance

One reason surge brakes are the most popular trailer braking technology is because the entire system is contained in the trailer itself. Periodic maintenance is required, but simply follow the manufacturer recommendations to get the most out of your hydraulic surge brakes. Mainly, maintenance will be required on the brake pads, brake lines, or brake fluid levels.

Your surge brakes have got your back, but always practice increased safety when driving your trailer with a tow vehicle. Pack your stuff tight, don’t want the inertia throwing everything around, leave plenty of room to brake, avoid speeding, and anticipate braking so you take it easy on your brakes and require less maintenance over time.

Your surge brakes will make or break your ride, and we’re here to make sure your trailer experience is the best it can be.