Your tractor is equipped with a K 80 coupling system with manual locking. What must you ensure when coupling a trailer?

The selected combination is correct because both actions, locking the retainer on the coupling system and adjusting the height of the trailer coupling, are essential for ensuring a safe and secure connection between the tractor and the trailer.

Locking the retainer prevents accidental disconnection while driving, which is crucial for road safety and compliance with German traffic regulations. Notably, the StVZO ( Straßenverkehrs-Zulassungs-Ordnung) emphasizes the importance of secure couplings to avoid accidents.

Adjusting the height of the trailer coupling ensures that the trailer is level when hitched, which is important for stability and handling during transport. Improper height adjustment can lead to difficulties in steering and increased wear on the vehicle.

While lubricating the coupling system may be beneficial for maintenance, it is not a mandatory requirement each time before use according to traffic regulations. Therefore, the correct actions are those that ensure safety and proper function while coupled.