CDL Exam

The brake system that applies and releases the brakes when the driver uses foot treadle is the _____ brake system.

• Service

• Trolley

• Parking

• Emergency

The emergency brake system will activate when the air pressure drops to between ___ psi and ___ psi.

• 20 and 30

• 25 and 45

• 20 and 45

• 20 and 40

The safety relief valve is located where?

• On the compressor

• On the governor

• On the first air storage tank

• On the second air storage tank

The safety valve is set to automatically open when the pressure is:

• 40 psi

• 75 psi

• 125 psi

• 150 psi

Which gauge helps you prevent engine failure, seizure, or breakdown?

• Power steering

• Oil pressure

• Ammeter

• Temperature

What do you use the dipstick to check?

• Oil level

• Windshield washer fluid level

• Coolant level

• None of the answers are correct

The S- cam

• Forces the brake shoes and linings against the inside of the brake drum.

• Controls the flow of air to each brake chamber.

• Pulls the brake shoes away from the drum, letting the wheel roll freely.

If your truck or bus has dual parking control valves, you can use air pressure from a separate tank to

• Stay parked twice as long without using up service air pressure.

• Release the spring emergency/parking brakes.

• Balance the service brake system when you are parked.

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.

What is a supply pressure gauge used for?

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

• To show how much pressure you have used in this trip.

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