What must you do after coupling up a single-axle trailer with overrun brakes?

After coupling a single-axle trailer with overrun brakes, it is important to follow these steps to ensure safety and proper functioning:

1. Checking that the brakes are working is crucial because overrun brakes rely on the trailer pushing against the tow vehicle to activate. If the brakes do not work properly, the trailer may not slow down correctly, increasing the risk of accidents.

2. Raising the jack wheel to the highest setting prevents it from touching the ground while driving. If left down, it can interfere with movement and damage the wheel or road surface.

3. Attaching the brakeaway cable to the motor vehicle's coupling ensures that if the trailer accidentally disconnects while driving, the brakes are applied automatically to stop the trailer and prevent it from rolling away uncontrolled.

Following all these steps is necessary for safe towing according to German traffic regulations. Missing any of these could compromise safety or cause damage.