Another common out of service violations found during DOT inspections are brake issues, usually brakes that are out of adjustment. Almost all brakes today are self adjusting, so the days of having to crawl around under the trailer with a 9/16th wrench are behind us, but even the self adjusters need a bit of “help” from time to time. To properly set up self adjusting brakes takes only a few minutes, and can be done while you are performing the air brake test of your pretrip inspection.
With the engine running, ensure the air system is fully charged, with all the brakes released. Push the brake pedal all the way to the floor, and release it 6 times in a row. The full pressure applications will cause the self adjusters to, well, self adjust. You can verify they have adjusted properly by rebuilding the air pressure to the maximum, rolling the unit forward and applying the trailer brakes using the hand valve. If the unit doesn’t come to a harsh stop, then the brakes need servicing immediately. You will learn through experience how to tell if the brakes are properly adjusted by the rolling test. An empty trailer will stop much harder than a loaded trailer, but if the trailer brake test does not stop you at all, then the brakes need service immediately. You can manually adjust self adjusting brakes, but all Canadian and some US jurisdictions require an endorsement on your drivers license, so unless you have that endorsement, do not attempt to adjust the brakes. Once satisfied your brakes are properly adjusted, you can carry on with the rest of your pretrip inspection, and get back on the road for another day.