Class B License Passenger Endorsement Practice Test

Brake shoes must be clean and dry because any slick film on the friction surface will dramatically reduce braking effectiveness. Oil, grease, or brake fluid on the shoes creates that slippery layer, causing reduced friction between the shoe and the drum and potentially leading to brake fade or failure, especially in demanding or emergency stops.

Oil on the engine isn’t related to the brake shoes, and dry brakes are the desired condition rather than something that should be present on the shoes. Paint on the shoes would also contaminate the friction surface, but the typical inspection focus is on the presence of oil, grease, or brake fluid.