Surge Brakes

Surge Brakes"Oh yeah, I know the trailer brakes are working, I could feel them grabbing on the hill!" To me, this was almost as reliable as "The cheque is in the mail!" when it came to testing trailers with surge brakes at the roadside.

This driver used the wrench I offered him to show me that there was no brake fluid in the master cylinder of the surge brake. Surprise!

Pre-Trip Inspection for Surge Brakes

As far as the surge brakes were concerned, this driver should have hooked up the trailer, checked the brake fluid level and condition and then conducted a tug test to ensure that they were working before he left the driveway.

It's simple, as aside from the wrench to check the brake fluid, all you have to do is set the breakaway brake and try to pull ahead. If the wheels don't lock, that's a sure sign that there is a problem. Make repairs before proceeding.

Low or Discoloured Brake Fluid Means Trouble

Brake fluid does not evaporate. If it is low, it is because there is a leak. It is definitely not good practice to top up the master cylinder and carry on.

Brake fluid is also hygroscopic, meaning that it will absorb water from the air. If the seal on the master cylinder is broken, the water that will accumulate in the fluid will rust the inside of the braking system rendering it useless.

Keep seals in good shape and follow your trailer manufacturer's recommendations for replacing the brake fluid.

Not a Rare Occurrence

I wish I could say that bad surge brakes were difficult to find, but they are not, especially on boat trailers.

If the trailer is loaded, the driver may be issued a Notice & Order #1 and the trailer may be removed by tow truck. In addition, depending on the trailer type and number of brakes not working, fines can range from $109 to $598.

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