An 8-chapter course for the CDL Air Brakes knowledge test. How the system makes and stores air, the service brake, gauges and warnings, spring brakes, dual systems, the air brake check, and braking on the road.
Most trucks and many buses stop on air. If you don't pass the Air Brakes knowledge test, your permit or license carries an air brake restriction — and the jobs that use air brakes go to somebody else.
If the truck or bus you'll train and test in has air brakes, you need this test. This course walks you through the whole system, one part at a time.
Already have a CDL with an air brake restriction? Chapter 1 explains exactly what federal rules require to take it off.
The Air Brakes test is full of numbers. The course shows which ones are federal law and which come from the CDL manual, so the one you give is the one the test wants.
Real screens from Chapter 1 of this course, and the free practice app explaining each answer with the rule behind it. Everything works on a phone, a tablet or a computer, and you pick up where you left off.
ELDT.Courses is listed on FMCSA's Training Provider Registry as an online theory provider. Search the registry for ELDT.Courses and you will find us, phone number and all: tpr.fmcsa.dot.gov/Search.
Every ELDT completion we report lands on your own driver record there by midnight of the second business day (49 CFR 380.717), so your state can see it before you test.
Each chapter is a narrated lesson followed by a chapter test. Built on 49 CFR Part 383 and the model CDL manual's Air Brakes section.
What the L and Z restrictions mean, how they get on a permit or license, what it takes to remove them, and how the knowledge test is built.
The compressor, governor, air tanks, check valves and safety relief valve — plus why water and oil in the tanks are dangerous and how to drain them.
The brake pedal, S-cam drum brakes step by step, slack adjusters, wedge and disc brakes, and why too much heat is a brake's enemy.
Supply and application pressure gauges, the low air pressure warning, the stop light switch, and the front brake limiting valve.
How spring brakes work, the parking controls you'll find on the dash, and what antilock brakes do and don't do.
How dual air systems split the work, service and emergency lines, the tractor protection valve, and what happens when a line breaks.
The walkaround checks, slack adjuster checks, and every step of the air brake check from the driver's seat, with the numbers for each.
Normal and emergency stops, braking with ABS, stopping distance, downgrades and brake fade, low air pressure on the road, and parking.
8 narrated chapters with a test after each one. Self-paced, lifetime access, direct instructor support.
Enroll Now — $35 →Free practice tests are a good way to check yourself. This course is where you learn how the system actually works.
| Typical practice-test site | ELDT.Courses | |
|---|---|---|
| Course content | A question bank and nothing else | Narrated chapters that teach the material before you're tested on it |
| Built from | Question banks with no sources shown | Primary sources: 49 CFR Part 383 and the model CDL manual |
| Current rules | No promise to keep up with rule changes | Updated when federal rules and regulations change |
| Quiz standard | Varies — often no defined threshold | 80% passing threshold, unlimited retakes |
| Instructor access | None | Direct email to the author, usually within 24 hrs |
Narrated chapters covering the full Air Brakes knowledge test, each followed by a chapter test. Self-paced.
The CDL Air Brakes study guide is included as a PDF download inside the course at no extra charge.
Stuck on a topic? Email me. You're not a ticket number here.
Your access doesn't expire. Come back for a refresher before a new job or a renewal.
When federal rules and regulations change, the course is updated — and enrolled students get the updates at no charge.
When you finish, a certificate with your name, the course and your completion date is emailed to you automatically. It's yours to print and frame — a keepsake of the work you put in, not a license or a federal record.
I spent 10 years as an OTR driver before founding ELDT.Courses. Air brakes are the system you trust every time you roll toward a stop sign with a load behind you. This course teaches what's happening between your foot and the wheel, so the gauges, warnings and checks make sense instead of being numbers to memorize.
Every chapter is built on primary sources — the federal regulations in 49 CFR and the model CDL manual the state tests are built from — and written fresh, not copied from someone else's training summary. Where a federal rule has changed and the printed manuals haven't caught up, the course tells you both, so you're not surprised on test day.
I've been around commercial trucking long enough to know what the standard endorsement course looks like — a recycled DMV manual, slow narration, and a quiz at the end. Drivers deserve better.
ELDT.Courses is what I wish I'd had when I was studying. Every chapter explains the why, not just the rule. Every quiz pulls from real test material. Every minute is paid for in attention, so I made sure none of them are wasted.
Have a question before you enroll? Pick a time and I will call you. Book a free phone call.
If you'll drive a commercial vehicle with air brakes, yes. Federal rules (49 CFR 383.95) put an air brake restriction on your permit or license if you don't pass the Air Brakes knowledge test. Removing it also requires the air brake pre-trip inspection on the skills test.
No. Air brakes is a restriction, not an endorsement. To keep the restriction off, you pass the Air Brakes knowledge test and take your skills test in a vehicle with full air brakes, including the air brake pre-trip inspection. No letter is added to your license — the restriction simply isn't there.
No. Federal ELDT (49 CFR 380.603) covers Class A and Class B training and the Passenger, School Bus, and HazMat endorsements. This course is prep for a state CDL knowledge test, built on 49 CFR Part 383. Nothing is submitted to the Training Provider Registry for this course.
Each chapter ends with a test, and you need 80% to pass it. You can retake any chapter test as many times as you need — each attempt draws a fresh set of questions. The state knowledge test is scored by your state's licensing agency; federal rules (49 CFR 383.135) set the passing score at 80%.
No. This is knowledge test prep. The course teaches every step of the air brake check so you know what it is before you practice it in a truck.
Try it risk-free. If you enroll and decide within 7 days that it's not for you — and you haven't started the course content — just email me and I'll refund you, no questions asked. Once you begin working through the material, the course is yours for life, including all future updates. Full terms are in our Terms of Service.
8 chapters. Built on 49 CFR Part 383. Lifetime access. Real instructor support.
It's all in there. The only thing missing is you.
Enrolling multiple drivers? Fleet and volume inquiries welcome — email terry@eldt.courses or call 1-814-304-7635.
