Brake Drum Wheel Cylinder problems of the 2019 Chevrolet Silverado 1500

At about 45 mph on a city street, I tried to apply the brakes but the pedal fell completely to the floor and about 98% of the braking ability was gone. I was able to ride the truck up onto the shoulder to slow down and stop. After restarting the vehicle, it seemed that the brakes were working again so I tried to make it to the dealership (about 1. 5 miles away). Accelerating back up to speed was very jumpy - almost as if the engine was being starved. After getting up to about 35 mph, the brakes engaged intermittently without me touching the brake pedal. I pulled back over and had the vehicle towed to the rest of the way to the dealership. While stopped and engine idling, I observed a very noticeable knock coming from the engine. The dealership diagnosed the problem and is replacing the master brake cylinder and lifters in the engine. This failure was extremely dangerous and I was lucky that it did not cause an accident.