MB Air Brake Test 13
- Perfect for first-time and renewal commercial applicants, and those adding endorsements
- Based on 2024 MB commercial driver's licence manual
- Triple-checked for accuracy
- Updated for October 2024
questions
correct answers to pass
passing score
- What function does the tractor protection system serve?
- When the driver releases the foot valve treadle in a vehicle without quick release valves, where would the application/service air from the brake chambers go?
- What issue does a broken return spring in the tractor protection valve cause?
- What is the main purpose of the trailer hand valve?
- Securing glad hands and coupler lines helps prevent what from happening?
- What term is used to denote the scenario when the tractor is operated without a trailer attached?
- Can the driver still use the foot valve once a trailer brake application is initiated via the hand valve?
- Approximately how many psi in the supply line are necessary to open the tractor protection valve, which is spring-loaded?
- The tractor protection system comprises how many valves?
- How many lines feed the tractor protection valve?
- If a tractor-trailer didn't have a tractor protection system, what could go wrong?
- What is the most widely used type of trailer supply valve?
- Which of the following is false? A trailer with two axles and spring parking brakes has
- A sudden air loss in the supply line has triggered the relay emergency valve to activate the trailer emergency brakes. They will remain applied until
- When the foot valve is released and the hand valve is activated, what is the result?
- Which of the following is not a key function of the trailer spring parking brake valve?
- If the primary reservoir's air pressure drops, is there enough pressure left for a few brake applications before the spring parking brakes are activated?
- What action must be taken with the trailer supply valve in the event of tractor reservoir air loss?
- From where is blended air drawn in a dual brake system?
- If the control line is ruptured or disconnected, when will action take place?
- A sudden air loss in the supply line has triggered the relay emergency valve to activate the trailer emergency brakes. How long can the system keep applying the brakes?
- Which statement is not true? The trailer brakes will stay applied until...
- If there's a loss of reservoir air pressure, what prevents the reservoir air pressure in the primary reservoir from escaping back to the supply reservoir and the ruptured line?
- What is the role of spring parking brakes in a trailer?
- What is not a function of the relay emergency valve?
- What types of trailers typically have a manual supply valve?
- What are the two positions that the manual trailer supply valve can occupy?
- What happens when the foot or hand valve is released during a brake application?
- Where would air pressure be lost if the compressor discharge line is ruptured?
- What has been added to minimize trailer brake lag time during foot or hand valve brake application?
- When should the trailer supply valve be open in terms of tractor pressure?
- For a dual air brake system, what does each section of the dual foot valve control?
- What occurs when there is a sudden loss of air pressure in the supply line, triggering the relay emergency valve?
- If the relay emergency valve has applied the trailer brakes in an emergency, what must be done to move the trailer?
- With a dual air brake system, when will the vehicle lose its braking ability?
- What system are most heavy vehicles currently using?
- What does it mean to 'charge' the trailer system?
- Should you use trailer air brakes to secure a parked vehicle left unattended?
- What initiates the application of spring parking brakes?
- What would happen if a trailer, not equipped with spring parking brakes, separated from the tractor?
- How is the foot valve divided in a dual air brake system?
- What should always be used as a safety measure when parking trailers without spring parking brakes?
- At what point do the low air pressure warning devices get activated in the primary and secondary circuits?
- ABS wheel sensors are found on at least how many sets of wheels?
- Is automatic traction control found in every vehicle?
- Which statement is incorrect? When all air is lost and the spring brakes have applied, the vehicle can be moved by...
- How should a vehicle equipped with ABS be driven differently from others?
- What does the ABS do when a slippery road surface causes engine brake to be engaged?
- What is sourced to supply the spring parking brake control valve?
- If a failure occurs in the primary circuit, at what pressure does the spring parking brake control valve exhaust the remaining air in the secondary circuit?