Trailer Brake Repair: Electric Brakes, Magnets and Breakaway

Electric trailer brakes fail in a few predictable ways: under-adjusted shoes, worn magnets, a bad ground, or a dead breakaway battery. Typical prices around Ocala: adjustment $80 to $150, new brake assemblies $350 to $600 per axle, a breakaway switch or kit installed $100 to $250. We do brake work where the trailer sits, and we test the brakes against your controller before we leave.

What we check on every brake job

• Adjustment. Dexter’s manual says brakes should be adjusted after the first 200 miles, at 3,000 mile intervals, or as use requires.
• Magnets. Dexter says to check the magnet face with a straightedge: it should be flat, and it must be replaced if worn unevenly or if any of the coil shows through the facing. The manual also gives a magnet resistance check with an ohmmeter.
• Shoes and drums. Lining wear, grease contamination and scoring on the drum.
• Wiring. Broken wires, loose connections and bad grounds. Dexter’s troubleshooting chart lists all three as causes of intermittent brakes, and it says to always ground trailer brakes through the connector.
• Breakaway system. Battery charge, switch, pull pin and cable.
• Controller. Whether the gain in your truck is set for the trailer and load. Dexter says best braking is a controller setting just short of wheel lockup.

Common brake jobs and typical prices

Full ranges are on the pricing page.

What Florida requires

The Florida Statutes put the requirement in plain words. Under s. 316.261(3), every trailer needs brakes on all wheels unless its gross weight is 3,000 lb or less and it weighs no more than 40 percent of the tow vehicle. Under s. 316.261(4), every trailer over 3,000 lb gross needs brakes that apply automatically on breakaway and stay applied for at least 15 minutes.

On an electric brake trailer, that second rule is the breakaway battery and switch. Dexter’s storage advice is to take the breakaway battery inside for long storage and charge it at least every 90 days. Sundowner’s manual says to check the breakaway system before each tow by pulling the pin and confirming the brakes apply, and it warns the breakaway is not a parking brake: chock the wheels.

The symptoms, and where to start

• No brakes at all. Start with the controller and the plug. See electric brakes not working or one wheel locking.
• One wheel grabs or locks. Dexter lists insufficient wheel load, loose or broken components and out-of-round drums. Insufficient wheel load is why an empty trailer can lock a wheel that never locks loaded.
• Brakes cut in and out. Broken wire, loose connection or faulty ground.
• Breakaway does nothing when the pin is pulled. See breakaway battery dead or not holding.

Brakes and bearings together

The brake drum is the hub, so a brake job means the hub is off anyway. That makes it the cheapest moment to repack the bearings: see wheel bearing service. The bearing and brake calculator prices both by axle count.

Before show season

A horse trailer that hauls to the winter circuit is stopping a heavy, moving load every weekend from October into April. That is the trailer that should have adjusted brakes, checked magnets and a charged breakaway battery before the first haul. If your brakes feel weaker than they did last spring, they probably are.