Free Air Brake Questions and Answers

Question 1

What produces the air necessary for an air brake system to function?

Accepted Answer

Under-hood compressor

Answer

An air brake system relies on compressed air to operate. The 'under-hood compressor,' also known as the air compressor, is the component specifically designed to draw in air, compress it, and then store it in reservoirs for use by the braking system. This ensures a continuous supply of pressurized air for safe vehicle operation.

Question 2

What is the typical operating pressure range of air brake systems?

Accepted Answer

105-125 PSI

Answer

Commercial vehicle air brake systems are designed to operate within a specific pressure range to ensure optimal braking performance and safety. The typical operating pressure for these systems is between 105 and 125 PSI. This range allows for effective brake application while preventing over-pressurization.

Question 3

When should the low-pressure warning system activate?

Accepted Answer

60 PSI

Answer

The low-pressure warning system is a critical safety feature in air brake systems, designed to alert the driver to a potential problem. It is mandated to activate when the air pressure in the system drops below 60 PSI. This warning ensures the driver is aware of insufficient air pressure before it becomes dangerously low, allowing time to address the issue.

Question 4

In a hand-pull test, how much push rod travel is necessary for the brakes to work?

Accepted Answer

1/2 inch

Answer

The hand-pull test, or manual slack adjuster check, is used to verify that the brakes are properly adjusted. For the brakes to work effectively and safely, the push rod travel should not exceed 1/2 inch when the brakes are applied. Excessive travel indicates that the slack adjuster needs adjustment, which could lead to reduced braking efficiency.

Question 5

What is the name for using the parking brakes or "spring" in an emergency?

Accepted Answer

Dynamiting

Answer

In the context of air brake systems, 'dynamiting' refers to the emergency application of the parking brakes, which are spring-activated. This term is used because it describes the sudden, forceful engagement of the spring brakes when air pressure is lost or intentionally released in an emergency, providing maximum stopping power.

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Free Air Brake Questions and Answers