Red Seal Truck and Transport Mechanic Practice Exam

What kind of fluid is typically used in a truck's hydraulic brake system?

1. Oil

2. Brake fluid

3. Water

4. Transmission fluid

The correct answer is: Brake fluid

The correct answer is brake fluid, which is specifically formulated for use in hydraulic brake systems. Brake fluid has properties that are crucial for its effectiveness in braking applications, such as a high boiling point to prevent vaporization under high heat and resistance to moisture absorption to maintain consistent performance. It is designed to provide the necessary hydraulic force that compresses the brake calipers, allowing the vehicle to slow down or stop. Brake fluid is also formulated to prevent corrosion and protect the internal components of the brake system, ensuring reliability and safety. Using other fluids such as oil or transmission fluid would not provide the necessary performance characteristics for braking and could lead to system failure due to insufficient pressure or damage to the hydraulic components. Water, while it may seem like a possibility, can lead to rust and boiling in the system, both of which would compromise braking effectiveness. Therefore, brake fluid is the ideal and mandated choice for hydraulic brake systems in trucks.