CLP - Commercial Learner's Permit Air Brake Systems Questions and Answers

Question 1

During a static air brake leakage test on a single vehicle, what is the maximum permissible pressure drop in one minute?

Accepted Answer

2 psi

Answer

For a single vehicle, the air pressure should not drop more than 2 psi in one minute during a static leakage test (engine off, brakes released). For a combination of two vehicles, the limit is 3 psi.

Question 2

A driver is performing an air brake check. At what pressure range should the low air pressure warning light and buzzer activate?

Accepted Answer

At or before 55-60 psi

Answer

The low air pressure warning signal (light and/or buzzer) must activate at a pressure of 55 psi or higher, and generally before the pressure drops below 60 psi. This alerts the driver to a potential issue before the spring brakes automatically engage.

Question 3

In a vehicle with a properly functioning dual air brake system, what is the expected time for the air compressor to build pressure from 85 to 100 psi?

Accepted Answer

Within 45 seconds

Answer

For dual air systems, the air pressure should build from 85 to 100 psi within 45 seconds with the engine at normal operating RPMs. A longer time may indicate a problem with the air compressor.

Question 4

A driver is operating a truck-tractor with a trailer. While driving, the low air pressure warning comes on. What is the safest immediate course of action?

Accepted Answer

Pull over and stop in the safest possible location.

Answer

When the low air pressure warning activates, it signifies a critical loss of air pressure that could lead to brake failure. The safest and required action is to stop the vehicle as soon as safely possible to diagnose and fix the issue.

Question 5

Which of the following brake systems is primarily responsible for applying and releasing the brakes when you use the foot pedal during normal driving?

Accepted Answer

Service brake system

Answer

The service brake system is the primary system used for slowing or stopping the vehicle during normal driving. It is controlled by the foot brake pedal (also called the treadle valve).

(CLP) Commercial Learner's Permit Practice Test

(CLP) Commercial Learner's Permit Practice Test

CLP - Commercial Learner's Permit Air Brake Systems Questions and Answers