Under what condition should a vehicle be rejected regarding the lining thickness of hydraulic and electric drum brakes?

The correct answer is based on the established standards for brake lining thickness, which is crucial for safe vehicle operation. Hydraulic and electric drum brakes require sufficient lining thickness to ensure they can effectively generate the necessary friction to stop the vehicle. If the lining thickness is less than 1/16 inch, it indicates significant wear that compromises braking performance and raises safety concerns.

At this thickness, the lining may no longer provide adequate contact or friction, leading to reduced braking efficiency, increased stopping distances, and potential brake failure. Therefore, the inspection guidelines dictate that any measurement below this threshold warrants a rejection during the inspection. This ensures that vehicles maintain necessary safety standards, protecting both the driver and others on the road.