Air Brake Test Reading 2 — Questions and Answers
Question 1: On a dual air brake system gauge, what does it mean when the air pressure for one of the two separate systems drops?
- Both systems instantly lose all pressure
- Only that one system is affected and the other still works (Correct answer)
- The parking brakes release automatically
- The engine shuts off
Correct answer: Only that one system is affected and the other still works
A dual air brake system has two separate systems, so a loss in one still leaves the other operational.
Question 2: When the low air pressure warning light comes on, at roughly what pressure does it typically activate?
- Below 60 psi (Correct answer)
- Below 100 psi
- Below 120 psi
- Below 150 psi
Correct answer: Below 60 psi
The low air pressure warning must activate before pressure drops below 60 psi.
Question 3: What does the air compressor governor control?
- The speed of the truck
- When the compressor pumps air into the tanks (Correct answer)
- The temperature of the brakes
- The position of the parking brake
Correct answer: When the compressor pumps air into the tanks
The governor controls at what pressure the compressor stops and starts pumping air into the reservoirs.
Question 4: Reading the manufacturer's plate, what is the purpose of the supply pressure gauge?
- Shows oil level
- Shows how much pressure is in the air tanks (Correct answer)
- Shows coolant temperature
- Shows tire pressure
Correct answer: Shows how much pressure is in the air tanks
The supply pressure gauge tells the driver how much air pressure is in the tanks.
Question 5: What does an application pressure gauge show the driver?
- How much air pressure is being applied to the brakes (Correct answer)
- Total tank pressure
- The fuel remaining
- The cab temperature
Correct answer: How much air pressure is being applied to the brakes
The application pressure gauge shows how much air pressure is being applied to the brakes.
Question 6: When reading brake instructions, increasing application pressure to hold speed on a downgrade is a sign of what?
- Brakes are working perfectly
- Brakes are fading and losing effectiveness (Correct answer)
- The tank is overfilled
- The governor has cut out
Correct answer: Brakes are fading and losing effectiveness
Needing more pressure to maintain speed indicates the brakes are fading.
Question 7: What does the safety relief valve in the air brake system protect against?
- Too little pressure
- Too much pressure (Correct answer)
- Frozen brake lines
- Worn brake pads
Correct answer: Too much pressure
The safety relief valve protects the tank and system from too much pressure.
Air Brake Test Reading 2
On a dual air brake system gauge, what does it mean when the air pressure for one of the two separate systems drops?