Which vehicle components must be free from major rust or corrosion?

The chassis and body of a vehicle must be free from major rust or corrosion because these components play a critical role in the structural integrity and safety of the vehicle. The chassis is the framework that supports the vehicle's body and components, and significant rust or corrosion can weaken this structure, leading to potential failures while driving. Similarly, the body of the vehicle is essential for protecting passengers and maintaining the overall aerodynamics and functionality of the vehicle. Any major rust or corrosion in these areas can compromise safety by affecting the vehicle's performance and stability.

The other components mentioned, while important, do not have the same structural significance as the chassis and body. Brakes and tires are crucial for safety but primarily relate to operational functionality rather than structural integrity. The interior components and the engine and transmission, although vital for vehicle operation, do not affect the vehicle's structural stability in the same way. Therefore, ensuring that the chassis and body are free from major rust or corrosion is a priority in maintaining vehicle safety and compliance with inspection standards.