Learn how to adjust a manual slack adjuster for your CDL Air Brake Test.

Learn how to how to find the specific numbers for the CDL In-Cab Air Brake Inspection.

As part of your CDL air brake inspection, you must test the tractor protection valve & system.

For truck or bus driver inspection of air brakes is 'MUST KNOW'!

From a mechanical standpoint, modern air brake systems are unlikely to fail.

Learn about air brakes for combination vehicles in the state of New York.

Getting your CDL? Learn about air brakes in the state of New York here!

For both a road test & your daily pre-trip inspection you must determine if the air brakes are in adjustment.

mobi On an air brake system, the air dryer filters moisture and other contaminants from the compressed air. Watch the video!

Applying the service brakes and doing a leak test will often locate a ripped service brake diaphragm.

Getting your CDL? Learn about air brakes in the state of New York here!

Getting your CDL in the state of New York - watch this video to learn air brakes!

Like a thermostat on a furnace, the governor controls the compressor.

For an air brake exam; you must know how to test the compressor.

All air brake systems have the same basic components.

The brakes on your car are the same as air brakes, only the power source is different

Although air brakes are more-or-less buletproof these, like all braking systems, have one failing: BRAKE FADE.

Downhill braking is an essential--potentially life saving--skill for bus, truck & RV drivers.

Going west to or east from Vancouver on the Trans-Canada with a big vehicle. Learn about the Coquihalla summit.

There are 4 types of foundation brakes you must know for your CDL test.

Must be used whenever two sources of air are used to operate a single device or system. For CDL air brake test, the driver must know there are 2 in the system.

The valve is an octagon-shaped red button on the dashboard.

OBSOLETE Independently applies and releases the trailer service brakes. Knowledge Test Question: This air brake control is not to be used for parking. Although most tractors are still equipped with hand valves, beyond a trailer service tug test, these air…

The tractor protection valve protect the tractors air supply from being depleted in the event of a trailer breakaway.

The system consists of the tractor protection valve and the trailer supply valve.

Applies and releases the truck or bus' parking brakes and is found on the vehicle's dash.

Activates the brake lights when a service brake application is made by the driver.

Applies the parking brakes of the air brake equipped vehicle indefinitely – if needed of course. The parking brakes are held in the “ON” position by the mechanical force of the springs; these spring parking brakes are held in the “OFF” position by system air…

OBSOLETE Used on some vehicles with dual air systems. This device provides a means of using the force of the spring brakes to assist in stopping a vehicle in an event of a failure in the rear (primary) air system.

Slack adjusters have three purposes: 1) To convert the forward linear motion of the push rod into rotary motion of the camshaft. The slack adjuster works on exactly the same principle as a box end wrench on a nut. 2) To act as a lever, thus generating greater…

All tanks have a safety valve.

Stores compressed air for braking and for other air operated accessories. The air tanks are the first fail-safe in the air brake system. In the unlikely event that the air compressor fell of the side of the engine, the air tanks (reservoirs) store enough air…

Several relay valve throughout the air brake system reduce brake lag, thus allowing the brakes to apply faster.

OBSOLETE Fills the trailer air tanks (reservoir) and applies and releases the trailer service brakes. The relay emergency valve also applies the trailer emergency brakes in the event of a trailer breakaway or normal disconnect. Knowledge Test Question: In the…

The quick release valve moves to reduce brake lag in the air brake system.

OBSOLETE To reduce application pressure to the steering axle by 50 % compared to the drive axle brakes, when required by reduced road conditions (rain, snow or ice). The system consists of a dash switch with 2 positions: Dry Road: 100% front wheel braking; in…

Warns the driver that system air pressure is critically low.

MUST KNOW The brake pedal applies the service brakes - truck, or truck and trailer brakes. In other words, the brake pedal brings the vehicle to a stop when it it depressed. SHOULD KNOW The foot valve operates the secondary and primary sub systems…

OBSOLETE Making a heavy service brake application while the parking brakes are applied. This is often an error of truck driving school students.

Allows the spring brakes to be manually released in an emergency - a dire emergency.

To stop the vehicle, brake linings rub against the brake drum. This action creates friction, converting the vehicle's forward energy of motion into heat energy, which stops the vehicle’s tires. If the tires have traction, the vehicle will come to a stop. The…

Brake faide is the only reason that a modern air brake system will fail.

A bobtail proportioning valve great increases braking safety owing to different weight distribution.

To reduce application pressure to the steering axle brakes during most braking situations. Reduced pressure to the steer axle brakes occurs for most braking applications. Only during hard braking is there equivalent pressure delivered to both the front and…

The gauges are in either pounds per square inch (psi) or Kilopascals (kPa). These measure the amount of air pressure in the primary and secondary air tanks.

Convert air pressure into a strong mechanical force to apply the foundation brakes.

A cattle chute with one-way gates allows the cows to only move in one direction – forward. A one-way check valve in an air brake system works exactly the same – it allows air to only move in one direction – forward through the system. The one-way check valves…

Using the pry bar method, confirm that the brake is in fact out of adjustment. After confirming that the brake is out-of-adjustment and it is equipped with a manual slack adjuster, complete the following steps to bring the brake back into adjustment. If one…

Depending on which province you're in, the air buildup time or compressor test has somewhat different paramenters. Still, all require that the diesel motor be at a fast idle. A fast idle on a diesel engine is between 900 &1200 rpm.

The National Safety Code madates that every driver of a commercial vehicle equipped with air brakes must check push rod travel every day. In many jurisdications, drivers are allowed to use the pry bar method; in others , they must use the applied stroke…

The National Safety Code madates that every driver of a commercial vehicle equipped with air brakes must check push rod travel every day as part of his/her pre-trip inspection. In some jurisdications, drivers must use the applied stroke method; in others, they…