The document describes an engine exhaust brake that is used as an auxiliary brake for slowing down vehicles travelling on long downhill gradients or in heavy traffic. The brake works by using compressed air and linkages to close a butterfly valve in the exhaust manifold, which cuts off the fuel supply when the foot control valve is pressed. This harness the engine's compression power to help slow the vehicle. The exhaust brake is effective at speeds below 40 kph and helps reduce fuel consumption.