What maintenance is necessary on trailers?

Your answer is correct because proper maintenance of trailers involves lubricating the fifth wheel and the towing fork.

The fifth wheel is the coupling device between the truck and the trailer, and lubricating it ensures smooth pivoting and reduces wear and tear, which is essential for safe and stable towing. Similarly, the towing fork, the part that connects to the fifth wheel, also needs to be lubricated for the same reasons.

Lubricating brake pads is not necessary for trailers, as brake pads themselves do not require lubrication; instead, the braking system may need inspection or adjustment. Therefore, focusing on the fifth wheel and towing fork ensures the trailer is properly maintained and safe to operate according to German traffic rules.