Sidestepping the Surge

Posted: November 1, 2013

By: Frank Lanier

Last year, a local yard converted my trailer’s surge drum brakes to TieDown disc brakes. I had to make two return visits to sort out the brakes not releasing fully and overheating when cruising down the highway. That seems to be sorted out, but I still have trouble backing up the trailer due to the surge brakes engaging in reverse. Is there any way to keep the surge brakes from activating when I’m just reversing to park my trailer in the driveway?
Most surge brake-equipped trailers have a manual override or brake lockout feature, which is simply a lever or pin you insert into the actuator to keep it from activating the brakes while reversing. If your trailer doesn’t have one of these, a down-and-dirty option is cutting a piece of wood just the right length to fit between the actuator and some fixed point on the trailer frame. When reversing, just wedge the piece of wood into place to keep the actuator from engaging. Just be sure to always disengage any manual brake lockout feature once you are done reversing, or the brakes will remain disabled when you resume towing.

Many surge brake-equipped trailers utilize a reverse solenoid, which automatically disengages the brakes when backing up (eliminating the need for a manual override). The solenoid is tapped into the vehicle’s reverse light system (via the trailer electrical plug). Shifting into reverse energizes the solenoid, which then reroutes the brake fluid back into the reservoir rather than actuating the brakes.

If this is a new problem (i.e., you were able to back up fine before), then the problem could be anything from a corroded or loose connection, a cut or broken “blue” wire (which is the one that activates the solenoid), a blown vehicle fuse (check to make sure you have reverse lights) or possibly a faulty solenoid.

If the backing problem has existed since you had the new brakes installed, it’s possible that the yard used the wrong plug or pin configuration, and the reverse solenoid is not being energized (assuming your trailer has one).

One final thing to consider: While the solenoid operates a valve that shuts off the flow of brake fluid from the actuator to the brakes, in many cases it doesn’t release pressure. As such, when you put your tow vehicle into reverse after stopping, if the trailer brakes were engaged when you stopped, they’ll still be on when you back up (even though the solenoid is energized and the valve is closed). After stopping, ease forward a bit, stop gently (so the brakes don’t engage) and then back up slowly.

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