CDL Air Brakes Flashcards

What type of air do air brakes use? (Select all that apply)

What are the three types of brake systems used in a commercial vehicle air brake system? (Select all that apply)

What is the name of the device that pumps air into the air storage tanks?

What is the alcohol evaporator's primary purpose?

What psi level is the safety relief valve set to open at?

Which of the following is the most common type of foundation brake?

Which of the following statements is true regarding front wheel braking?

At what air pressure must the low air pressure warning signal come on?

Which of the following statements regarding spring brakes is true?

Which of the following devices indicates how much pressure you have in your air tanks?

What is the primary purpose of a front brake limiting valve?

Air Brake System Overview

Air brakes utilize compressed air for operation, providing reliable stopping power for large vehicles when properly maintained.

Types of Brake Systems

The air brake system in commercial vehicles includes service brakes, parking brakes, and emergency brakes.
Anti-lock brakes are supplementary, serving as a safety feature rather than a primary component.

Key Components

The air compressor is responsible for pumping air into storage tanks, while the governor regulates when this air pumping occurs.
An alcohol evaporator injects alcohol into the air system to minimize ice formation during cold weather.
A safety relief valve opens at 150 psi to prevent excessive pressure in the air storage tank.

Foundation Brakes

S-cam drum brakes are the most prevalent type of foundation brake, with wedge and disc brakes being less common.

Front Wheel Braking

Front wheel braking remains effective under various conditions and is not likely to cause skids, even on icy surfaces.
Vehicles manufactured before 1975 may feature a front brake limiting valve that should be positioned to "normal."

Air Pressure Indicators

A low air pressure warning signal activates when pressure decreases below 60 psi, alerting the driver to potential risks.
Supply pressure gauges display the current pressure in the air tanks, essential for monitoring system health.

Spring Brakes

Spring brakes are primarily held by mechanical force and are designed to engage automatically when air pressure drops below 45 psi.

Additional Brake Functions

A front brake limiting valve reduces air pressure to front brakes by half, which can enhance control during certain driving conditions.

Test your knowledge on air brake systems used in commercial vehicles with these flashcards. Each card presents crucial concepts, definitions, and types of air utilized in braking systems. Perfect for anyone preparing for the CDL exam or wanting to refresh their knowledge of vehicle safety.