CDL Air Brakes Study Guide 2024 [PDF] Free Download for Commercial Driver’s License Permit Test (CDL) Air Brakes Endorsements in the USA, UK, and Canada. This study guide would help your upcoming CDL Permit test 2024 written exam.
Air Brakes Endorsement Test: Many commercial drivers must be qualified and/or authorized to operate air brake-equipped vehicles and must demonstrate knowledge of air brake systems to ensure they are fully aware of the proper method of Inspecting an air brake system and identifying problems that can OCCUT when the system malfunctions. All Class A commercial drivers are required to pass the Air Brakes Test and some Class B commercial drivers are required to pass the exam.
CDL Air Brakes Study Guide
Air brakes are used on heavy vehicles for a number of reasons:
- Air brake systems use a much greater force to apply the brakes than hydraulic braking systems do. This greater force is needed to cope with the heavy loads of commercial vehicles.
- Air brake systems are more tolerant of small leaks. The smallest leak in a hydraulic system could result in brake failure. An air brake system includes a compressor to generate more compressed air as needed.
- Air brakes are used on heavy vehicles because they have proven they are capable of stopping these vehicles safely.
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After reading this CDL Air Brakes Study Guide PDF you will be able to:
- Basic Air Brake Systems
- Schematic Air Brake System
- Air Compressor
- Governor
- Maximum Air Pressure
- Air Tanks (Reservoirs)
- Safety Valve (150psi)
- Drain Valves
- Air Lines
- Brake Pedal (Service Brakes)
- Foundations Brakes
- Wedge Brakes
- Review Questions
- Air Brake Fundamental Components
- Purpose of Governor
- Failsafe – Air Tanks
- Drain Valves – Purpose
- Safety Valve Sound
- Question for Smart Driver
How to Check the Air Brake System?
The Seven-Step Air Brake check -DO THIS AT PRE-TRIP INSPECTION when performing the Skills Test portion of the CDL exam. Designed to test the governor cut-in and cut-out pressures, air pressure leakage: warning buzzer, brake valves, and air pressure rebuild rates. Brakes off mean the yellow and/or red valve is pushed in (on = valve out).
- The engine on Brakes on — check gauges to make sure the governor cuts the compressor off at 120 psi. Pump brakes until the pressure drops below 100 psi to make sure the governor cuts the compressor on.
- Engine off Brakes off— do not touch brakes — watch gauges to make sure pressure does not drop more than 3 psi in one minute.
- Press and hold the brake pedal — watch gauges to make sure pressure does not drop more than 4 psi in one minute.
- Tum key on Engine off/ Brakes off— pump brake until the pressure drops to 60 psi — warning buzzer should sound at or before 60 psi.
- Continue pumping brakes until reaching 20 to 40 psi — Emergency (red) and Service (yellow) brake valves should pop out turning brakes on.
- Rebuild air pressure in the tank — hold the accelerator at 1500 RPM. Watch air gauges and notice that the pressure rate of build between 85 psi and 100 psi should not take more than 45 seconds.
- Perform tug tests. Tug against Parking Brake only. Tug against Emergency Brake only. Tug against Hand Brake only.
Air Brake Endorsement Requirements in the USA
CDL Air Brake Requirements. For CDL purposes, a vehicle’s air brake system must meet the above definition and contain the following, which will be checked during the vehicle inspection test:
- Air gauges.
- Low pressure warning device(s).
If the vehicle you use for your road test does not have these components, your vehicle will not be considered as having an air brake system and you will have a “No Air Brakes” (“L”) restriction on your CDL.
A full service brake application must deliver to all brake chambers not less than 90 percent of the air reservoir pressure remaining with the brakes applied (CVC §26502).
The parts of these systems are discussed in greater detail in the following paragraphs.
Air Brake Endorsement Requirements in Canada
In Ontario, most large commercial vehicles are equipped with an air brake system. You must have an air brake endorsement on your driver’s licence to drive these vehicles.
The purpose of this handbook is to introduce you to the knowledge and skills you need to drive a vehicle with air brakes in a safe and lawful manner. It contains the information you need to prepare for the air brake endorsement examination. Air brake examinations are conducted at DriveTest Centres.