Podcast
Questions and Answers
During normal driving, spring brakes are usually held back by?
During normal driving, spring brakes are usually held back by?
air pressure
The brake pedal in an air brake system controls what?
The brake pedal in an air brake system controls what?
the air pressure applied to put on the brakes
The brake system that applies and releases the brakes when the driver uses the brake pedal is what system?
The brake system that applies and releases the brakes when the driver uses the brake pedal is what system?
service system
All air braked equipped vehicles must have what?
All air braked equipped vehicles must have what?
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If your truck or bus has dual parking control valves, you can use pressure from a separate tank to do what?
If your truck or bus has dual parking control valves, you can use pressure from a separate tank to do what?
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The most common type of foundation brake found on heavy vehicles is the?
The most common type of foundation brake found on heavy vehicles is the?
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Parking or emergency brakes of trucks and buses can be legally held on by?
Parking or emergency brakes of trucks and buses can be legally held on by?
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If your vehicle has an alcohol evaporator, it is there to do what?
If your vehicle has an alcohol evaporator, it is there to do what?
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What may happen if you don't keep the alcohol evaporator filled with alcohol?
What may happen if you don't keep the alcohol evaporator filled with alcohol?
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The most important thing to do when the low air pressure warning comes on is?
The most important thing to do when the low air pressure warning comes on is?
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The driver must be able to see a low air pressure warning that must come on before pressure in the tanks fall below what?
The driver must be able to see a low air pressure warning that must come on before pressure in the tanks fall below what?
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Under normal conditions, in order to engage the parking brake the driver must?
Under normal conditions, in order to engage the parking brake the driver must?
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To check the free play of manual slack adjustors on s-cam brakes, you should park on?
To check the free play of manual slack adjustors on s-cam brakes, you should park on?
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If your vehicle has an alcohol evaporator, every day during cold weather you should?
If your vehicle has an alcohol evaporator, every day during cold weather you should?
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For air brake systems in good condition, the air compressor should start pumping at?
For air brake systems in good condition, the air compressor should start pumping at?
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A straight truck or bus system should not leak at a rate of more than?
A straight truck or bus system should not leak at a rate of more than?
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A slack adjustor probably needs adjustment if it moves more than?
A slack adjustor probably needs adjustment if it moves more than?
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If you are driving down a steep downgrade and you have reached your safe speed of 40 mph, you should apply the service brakes until your speed reaches what?
If you are driving down a steep downgrade and you have reached your safe speed of 40 mph, you should apply the service brakes until your speed reaches what?
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The use of brakes on a long and/or steep downgrade is only a supplement to what?
The use of brakes on a long and/or steep downgrade is only a supplement to what?
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Under ideal conditions, a truck with air brakes going 55 mph would require a stopping distance of what?
Under ideal conditions, a truck with air brakes going 55 mph would require a stopping distance of what?
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Emergency stab braking is when you?
Emergency stab braking is when you?
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The braking power of the spring brakes depends on what?
The braking power of the spring brakes depends on what?
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If you must make an emergency stop, brake so you?
If you must make an emergency stop, brake so you?
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The proper method of braking when going down hills is?
The proper method of braking when going down hills is?
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ABS changes what?
ABS changes what?
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If your ABS is not working, you should?
If your ABS is not working, you should?
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The stop light switch does what?
The stop light switch does what?
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If air pressure does NOT build up to normal within the correct amount of time, what may happen?
If air pressure does NOT build up to normal within the correct amount of time, what may happen?
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If the spring brakes are on, when should you push the brake pedal?
If the spring brakes are on, when should you push the brake pedal?
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If your truck's air compressor has its own oil supply, when should you first check the oil level?
If your truck's air compressor has its own oil supply, when should you first check the oil level?
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The safety valve is set automatically to reduce pressure in the tanks at what psi?
The safety valve is set automatically to reduce pressure in the tanks at what psi?
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Study Notes
Air Brake Systems Overview
- Spring brakes are typically held back by air pressure during normal driving.
- The brake pedal in an air brake system controls the air pressure to activate the brakes.
- The service braking system applies and releases brakes using the brake pedal.
Mandatory Equipment and Safety
- All vehicles equipped with air brakes must have a supply pressure gauge.
- Parking control valves allow emergency use of pressure from a different tank to release spring brakes.
- Trucks and buses can legally maintain parking or emergency brakes using spring pressure.
- Vehicles should feature an alcohol evaporator to minimize ice formation in cold weather.
Maintenance Concerns
- Failure to keep the alcohol evaporator filled can lead to ice in tanks and brake failure.
- Daily checks of the alcohol level in the evaporator are advised during cold conditions.
- Slack adjustors should not move more than one inch when manually pulled to indicate proper adjustment.
Operational Guidelines
- Low air pressure warnings must activate before tank pressure falls below 60 psi.
- To engage the parking brake under normal conditions, the driver must release air from the system.
- A properly functioning air brake system should initiate compressor activity at 100 psi.
Performance Metrics
- A straight truck or bus should not exhibit an air leak greater than 2 psi per minute when idle.
- A truck at 55 mph may need over 300 feet to achieve a complete stop under ideal conditions.
- Effective control is crucial when driving downhill; service brakes should reduce speed safely without solely relying on them.
Emergency Procedures
- In emergencies, perform stab braking by fully engaging brakes and releasing to regain wheel rotation.
- If an emergency stop is essential, brake in a manner that keeps the vehicle steerable and aligned.
- Under ABS conditions, adjust braking approach during emergencies to enhance control; if ABS malfunctions, drive normally but seek service.
Brake System Operations
- The safety valve is automatically set to relieve pressure in the tanks at 150 psi.
- Do not push the brake pedal while spring brakes are engaged to avoid damage.
- Check the oil level of the air compressor with its own supply before driving to ensure proper function.
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Description
This quiz covers the essential components and safety measures of air brake systems, including the function of spring brakes and the importance of maintenance practices. Test your knowledge on mandatory equipment and maintenance tips to ensure optimal performance in cold weather. Perfect for truck and bus operators!
