Some owners of trailers may notice that the brakes of those trailers may fail to disengage after the driver has braked suddenly. The root cause of this problem needs to be diagnosed correctly so that an appropriate solution can be implemented. This article discusses some of the common causes of locked trailer brakes.
Brake fluid is supposed to flow freely into and out of the orifice depending on the presence or absence of pressure exerted upon it. However, the brakes of your trailer may fail to release in case the orifice has a clog on its output side. That clog will form a barrier that will prevent the brake fluid from flowing back into the orifice after you release the brake pedal of the tow vehicle.
Trailer brakes operate by detecting the pressure exerted by the trailer on the tow vehicle. An actuator compresses the piston so that it pushes the fluid towards the brake rotor. The rotors then exert pressure on the brake pads with a force that is equivalent to the pressure acting on the piston. The brakes may fail to release in case the slide assembly of the actuator jams in the compressed position. The piston will therefore stay engaged until the slide assembly is fixed.
The piston of the trailer's master cylinder may jam after engaging the brakes. This will prevent the return spring from pushing the piston to its normal (relaxed) position. Consequently, the brake fluid will remain exerting pressure on the brake rotors. The brakes cannot release their hold on the wheels in such a situation.
Damaged Push Rod
Another cause of trailer brakes that won't release is a defect in the push rod that acts on the piston in the master cylinder. For example, a warped push rod will not work properly to engage and disengage the piston. This can cause the brakes to lock completely or operate erratically. The only remedy to this problem is to replace or repair the push rod so that it works without any impediments.
It is very hard for a layperson to pinpoint which of the factors above is causing the brakes on his or her trailer to fail to release after being engaged. The best course of action should be to call a trailer repair professional so that a detailed inspection of the braking system can be performed. An appropriate solution will then be recommended so that the brakes can start working normally again before you resume towing that trailer.