Electric vs Hydraulic Trailer Brake Systems -What You Should Know

Brakes are rarely considered until we have cause to be overwhelmingly thankful for their existence. Many sailboats and powerboats make a towed trailer heavy, especially going downhill, so it is worth examining the differences between electric and hydraulic braking systems, drum and disc brakes. We discuss why a boat trailer can have an electric brake system without concern and what you should be aware of with a hydraulic brake system.


Using the wrong braking system can have terrible consequences; your brakes can overheat or result in a longer stopping distance threatening your and other drivers’ safety; you need to be aware of the weight you are hauling and choose your brakes accordingly to protect you and all others you encounter on the highway.


Visit our extensive selection of hydraulic (surge) and electromagnetic (electric) brakes on our brake page, and their related accessories (individually highlighted below) Please ask us any questions you may have; we are experts in all things trailer parts and axle related. Call Standard Axle at (519) 451 1116 Mon – Fri, 8-5 pm.


Your trailer has its own braking system separate from your tow vehicle. And that’s a very good thing.

Many customers don’t even realize that a trailer has a braking system. Not knowing can mean real trouble, especially if you’ve purchased a used trailer without having its brakes inspected. 



A boat trailer can have an electric brake system without concern.

Surge/ hydraulic braking systems are the most common on a boat trailer since water doesn’t pose a concern for hydraulic brake systems. It is (wrongly) also believed electric braking systems are not water-proof. Now, electric braking systems are well insulated and use heat shrink connections, so are fine for submerging. Of course, rinsing the components with fresh water afterward will extend the life of the magnets in the electric brake connection. Unplugging the brakes before submerging is still an option, but it won’t be a concern as long as the electric lines are kept in good shape.  

If, after reading our article, you would like to know more about switching brake systems, don’t hesitate to contact our competent staff at London, Ontario’s Standard Axle.


Trailer brakes (like the tow vehicle’s) are either disc or drum brakes; both types of brakes are components of hydraulic and electric braking systems.

Disc brakes employ rotors inside each wheel that brake pads squeeze against to create the friction required to stop. They tend to have greater advantages, especially regarding their stopping power, making them a better choice for trailers. Disc brakes can easily replace existing drum brakes. Disc brake rotors reduce the heat caused by friction by keeping the air inside to maintain a cooler temperature. 

Drum brakes use friction similarly to disc brakes but are hollow, cylindrically shaped drums that rotate in the same direction as the wheel, with brake pads lining the inside. When the brakes are applied, the pads expand against the rotating sides of the drum, using friction to slow down the vehicle.

Brake pad materials are used in both brake types, drum and disc, and can vary in their materials and quality.


The two types of braking systems:

1) Electromagnetic (electric) brakes

The tow vehicle’s brake pedal pressure activates an electric braking system; when the tow vehicle brakes are pushed, voltage is sent to the trailer’s electromagnetic actuators, engaging the trailer brakes first, which is safer for downhill driving. We recommend using electric over hydraulic brakes for any boat heavier than 1,550 kg (3,500 lbs) 

Brake controllers: Electric brakes on trailers include the utilization of a separate brake controller (mounted near the dash in the tow vehicle) that adjusts the amount of braking pressure going to the trailer. The ability to adjust the gain means less deterioration of the tow vehicle brake system.

  • When you’re going downhill or towing heavy weight, set your brake controller gain higher to adjust the braking responsibility more toward the trailer
  • When travelling uphill or towing a light load, set the gain to a lighter setting


2) Hydraulic (surge) brakes 

The difference between hydraulic and electric brakes lies in the advantage of the independent brake control with the electric brake controller for the trailer brakes. 

Hydraulic brakes utilize hydraulic fluid and its pressure to stop wheels from turning. The faster you slow down, the more hydraulic braking pressure is applied to the trailer brakes. 

Pressure (or braking) only reaches the trailer’s brakes when the hydraulic cylinder on the tow vehicle is triggered (pushing the fluid from a master piston into the other two pistons, which push together to cause friction against the disc brakes.) The actuator on the trailer moves within the coupler frame allowing the pressured hydraulic fluid to move through the brake lines to the brakes as dictated by the braking pressure of the tow vehicle.

Also, see our brake line kits.


Hydraulic brakes cause concern when backing up a trailer, especially on an incline (like a driveway). The answer to how to fix it is here:

  • When backing up a trailer, especially on an incline, hydraulic braking systems will sense the pressure on the tongue as if you are applying the brakes. The actuator engages the trailer brakes, and you cannot continue backing up.
  • There should be a lock-out pin or lever already on the tongue that you can engage to allow backing up on an incline. When you move forward again, it automatically resets. 
  • Sometimes, disc brakes have less effect.
  • If your braking system is hydraulic, address this before heading out for a holiday. 


Call Standard Axle with questions or orders by phone at (519) 451 1116 Mon – Fri, 8-5 pm. 

Shop and place your online order here.