CDL Air Brake Tests [2016]

"I would like to perform the Air Brake Tests.”

 

1 - APPLIED TEST

With a fully charged air system (125 psi), your key turned to the “accessory” position (so the gauges will function), stopwatch, and wheels chocked (if necessary to make sure you won’t roll).

"My first test is the Applied Brake Test. I will put the rig in gear, then shut off the engine. I will release the parking brake and wait for the gauges to stabilize. My primary and secondary gauges are presently at _____ psi. I will now fully apply the service brake, and I should not lose more than 3 psi in 60 seconds."

Have your watch ready to time 60 seconds. Carefully hold 50-60 psi on the service brake pedal for 60 seconds. You should not lose any air pressure. At the end of 60 seconds, you should be able to tell the examiner...

"The primary and secondary gauges are still at _____ psi. I have not lost more than 3 psi. It was a successful test.”

2 - LOW AIR WARNING TEST

Start the engine with the vehicle in park, then shut the engine off when you have enough air pressure so that the low pressure warning signal is not on.

"My next test is the Low Air Warning Test. A light or buzzer must come on no lower than 55 to 75 psi."

Pump the service brake pedal slowly enough to be able to tell if the warning device sounds. When it does, tell the examiner...

"The light and buzzer came on at _____ psi. It was a successful test.”

Again, both primary and secondary gauges should closely agree.

Start the engine and build back maximum psi before beginning the next test.

3 - POP OUT TEST

Make sure the wheels are chocked, if necessary. Shut the engine off. Release the parking brake.

“The next test is the Pop Out Test. I will reduce the air tank pressure by stepping on and off the brake pedal. The parking brake valve should pop out between 20 and 45 psi, causing the spring brakes to come on.”

When the parking brake pops out, announce to the examiner, “The parking brake popped out at ______ psi. It was a successful test.”

4 - CUT OUT TEST

"My next test is the Cut Out Test. At fast idle, the governor must cut out prior to 130 psi. My primary and secondary gauges are presently at _____ psi."

If the air pressure is already too high, you may need to bleed off some air pressure by stepping on the service brake pedal. Now, start the engine and build up air pressure by accelerating the engine to about 1,100 RPMs. When the governor cuts out, tell the examiner...

"Cut out occurred at _____ psi. It was a successful test.”

The primary and secondary gauges will read about the same.

5 - CUT IN TEST

To perform this test, the air pressure for the vehicle cannot be rising when the engine is running. With the engine idling, slowly pump the brake pedal to reduce the air tank pressure. Watch the air pressure gauge between pumps to identify when the compressor cuts in (needle starts to rise). This should occur no lower than 100 psi.

"My next test is the Governor Cut In. Cut in must occur no lower than 100 psi."

Of course, you are giving a close approximation of exactly when the governor cut in takes place. You can tell that the governor has cut in by when the gauge needle begins to move upward. You will have to wait a moment after each press of the service brake pedal to tell if the needle is actually moving. When the cut in occurs, tell the examiner...

"Cut in occurred at _____ psi. It was a successful test.”

Again, the primary and secondary gauges will read about the same.

6 - PARKING BRAKE TEST

"My next test is the Parking Brake Test. With the engine running and the parking brake on, I will put the rig in gear. There should be no movement."

Make sure the engine is running. Put the parking brake on, then put the rig in gear. After the rig does not move, tell the examiner...

"Since the rig did not move, it was a successful test."

7 - SERVICE BRAKE TEST

With the engine still running, and waiting for normal air pressure to build up, tell the examiner…

“My last test is the Service Brake Test. I will release the parking brake, and as the vehicle moves forward slowly, I will apply the brake pedal."

Release the parking brake, move forward slowly [5 mph], and apply the service brake, then tell the examiner…

"With no unusual pulling or delay, it was a successful test.”

“That completes the Air Brake Tests.”

CDL Air Brake Tests [2016]

https://www.dmv.ca.gov/portal/dmv/?1dmy&urile=wcm:path:/dmv_content_en/dmv/pubs/cdl_htm/sec5

Tag: Work, Air Brake Tests, CDL