Air Brakes 2

On large, heavy vehicles, the parking or emergency brakes must be held on by something that cannot leak away, such as

• Air pressure.

• Spring pressure.

• Hydraulic pressure.

The air compressor governor controls

• When air is pumped into the air storage tanks.

• The air pressure applied to the brakes.

• The speed of the air compressor.

Your vehicle has a dual air brake system. If a low air pressure warning comes on for just one of the two systems, what should you do?

• Stop and park safely. Continue only after the system has been fixed.

• Reduce your speed and drive to the nearest garage for repairs.

• Reduce your speed and test the remaining system while you’re driving.

The safety valve is set to automatically reduce pressure at

• 150 psi

• 50 psi

• 100 psi

What is the supply pressure gauge used for?

• To show how much pressure is in the air tanks.

• To show how much pressure is going to the brake chambers.

• Show how much pressure you have used in this trip.

The braking system that applies the brakes when the driver presses the brake pedal is the_____ brake system.

• Emergency

• Parking

• Service

With S-cam drum brakes, when the brake chamber fills with air, air pressure pushes the pushrod out, moving the _____ and thus rotating the _____

• Brake camshaft; tie rod

• Slack adjuster; tie rod

• Slack adjuster; brake camshaft

On a long or steep downgrade, once you have reached your “safe” speed, brake until you are traveling

• 5 mph slower.

• 10 mph slower.

• 15 mph slower.

The parking brake control

• Applies the brakes during normal driving.

• Lets the air out of the brake chambers.

• Applies the brakes in the event of an emergency.

If your vehicle has an alcohol evaporator, you should _____ daily in cold weather.

• Completely replace the alcohol

• Check the alcohol level and refill as needed

• Check the oil for alcohol content