Which action triggers air into the brake chamber?

Which action triggers air into the brake chamber?

• A. The parking brake is set
• B. The engine is started
• C. Compressed air enters the brake chamber
• D. The temperature rises

Answer: (C)

In an air brake system, brakes are applied by sending compressed air into the brake chambers. The action that actually triggers air into the brake chamber is the flow of compressed air from the reservoirs through the brake valve into the chamber. When this air enters, it pushes the diaphragm inside the chamber, which converts that pressure into a mechanical force to apply the brakes. The other options don’t cause the chamber to fill with air directly: starting the engine builds system pressure but doesn’t itself push air into the chamber; a rise in temperature doesn’t fill the chamber; and setting the parking brake involves holding or releasing via air/ spring mechanisms, not directly filling the brake chamber with air.

In an air brake system, brakes are applied by sending compressed air into the brake chambers. The action that actually triggers air into the brake chamber is the flow of compressed air from the reservoirs through the brake valve into the chamber. When this air enters, it pushes the diaphragm inside the chamber, which converts that pressure into a mechanical force to apply the brakes.

The other options don’t cause the chamber to fill with air directly: starting the engine builds system pressure but doesn’t itself push air into the chamber; a rise in temperature doesn’t fill the chamber; and setting the parking brake involves holding or releasing via air/ spring mechanisms, not directly filling the brake chamber with air.