Test Your Trailer Brakes Like a Pro

Sunday, October 29, 2017
Posted by Blue Ridge Trailers


We all know that gut-wrenching feeling of coming too close to another car’s tail lights.

For the safety of ourselves, our cargo, our horses, and others on the road, it’s important to prepare for those scary moments when a car veers in front of your tow vehicle or stops short. If you’re not 100% sure that your trailer brakes are functioning, you’re not ready for the road.

Blue Ridge Trailers is a Virginia trailer inspection station with years of experience testing brake function and other trailer safety components. We wanted to share our quick tip for how to test trailer brakes effectively before every drive, so you can stay safe and relaxed on the road.

Note: this tip in no way replaces comprehensive trailer inspections. It’s crucial (not to mention required by law in Virginia and many other states) to get a state certified trailer inspection every year to ensure all of your trailer’s safety systems are in good working order.

Today we’ll be focusing particularly on how to test trailer brakes in electric brake systems, which are found in your typical tandem axle utility or horse trailer. Most trailers have two brakes on each axle–so if you’ve got a tandem axle trailer, you’ll have four brakes.

With electric trailer brake systems, you’ll also have a brake controller (a.k.a. a brake box), which is mounted in your tow vehicle. The brake controller sends electricity to the brakes themselves, through the trailer plug, when you press the brake pedal in your tow vehicle.

The brake controller setting will dictate how much braking power will be transferred by the brake pedal. A digital brake controller can be set to automatically override the existing setting, giving you maximum braking power in the event of an emergency.

The thing is, it’s not always easy to tell which (if any) trailer brakes are working just by pressing the pedal during a test drive.

Instead, you’ll want to look for a slide bar on your brake controller. It should go from 0 to 10 or will have an indicator light. Check your brake controller manual if you don’t find it right away.

Once you’ve located the slide bar, start pulling on it gradually as you drive forward slowly. You should feel stronger and stronger resistance as you move from 0 to 10. If you’re not feeling much or any braking as you approach 10, you know you’ve got a problem.

Because this testing method bypasses the truck pedals, you’ll get a more accurate sense of trailer brake function. You’ll know that any resistance is coming exclusively from the trailer itself, not the tow vehicle brakes.

If your trailer doesn’t pass your brake test, it’s likely due to one or more common problems:

  • Corrosion of the wiring or brake components. This sometimes occurs if a trailer sits parked for weeks or months at a time.
  • Poorly adjusted brakes.
  • Delaminated and/or grease-saturated brake shoes.
  • Missing components such as a slack adjuster. As always, your trailer manual and a professional trailer inspector can help you diagnose issues and get your brakes running smoothly.

Got questions about how to test trailer brakes on your own trailer or other trailer safety concerns? Blue Ridge Trailers is always happy to offer our expertise. Contact us online or call us at (434) 985-4151 to speak to our staff.