What control and service work has to be carried out regularly on a fifth wheel?

Your answer is correct because regular lubrication of the fifth wheel is necessary to ensure smooth articulation between the tractor and trailer, preventing excessive wear and potential damage. Additionally, checking the fixing to the frame is important to ensure the fifth wheel is securely attached, maintaining safety during driving. The option stating fifth wheels are always maintenance-free is incorrect; periodic maintenance is essential for safe operation. In German traffic regulations and vehicle maintenance guidelines, these checks help avoid accidents caused by faulty coupling.