A brake out of adjustment is the highest frequency violation during a roadside inspection!

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Professional drivers typically will maintain a space cushion between them and the vehicles in front of them. When applying the brakes they will usually apply the brakes with 15% to 25% air application. Only in a defensive action will a driver apply the brakes with greater than 60% air application. These braking incidents are referred to as “Panic Stops” or “Rapid De-acceleration Occurrences.” Analysis reflects that most professional drivers will require less than 6 of this type of brake application per 1,000 miles driven.

Most International trucks are equipped with a “Stroke Sensitive” automatic adjuster. This type of slack adjuster adjusts the brakes on the return stroke.

This adjustment occurs only when the application is greater than 60%. The better the driver, the less opportunity there is for the automatic slack adjuster to make a brake adjustment. To ensure that the brakes are always in adjustment, we recommend the following:

An automatic slack adjuster will adjust approximately ½ inch with every 10 full brake applications.

Including this procedure as part of your pre-trip inspection will ensure that your brakes are always fully in adjustment. In the event of a roadside inspection, repeat this process while waiting your turn in line for the inspection process. This will insure that you are not red-tagged, due to a slack adjuster “Out-of-Service” condition or receive a violation. After completing this procedure and the brakes are still not adjusted or are inspected and found to be out-of-service, then it indicates there is a problem with the adjuster, with the adjuster’s installation or with related foundation brake components.


The following is the Air Brake Inspection Procedure that will be used by the CVSA inspectors during Brake Safety Week:

Inspection Items:

  • Driver License
  • Registration
  • Low Air Warning Device
  • Pushrod Travel (Adjustment)
  • Brake Linings/Drums
  • Air Loss Rate (If leak detected)
  • Tractor Protection System

Operation Air Brake Inspection Procedure:

Step 1: Choose the Inspection Site

Step 2: Safety Considerations

Step 3: Check Air Brake Mechanical Components

Step 4: Check Steering Axle Air Brake Mechanical Components

Step 5: Check Brake Adjustment

Step 6: Build the Air Pressure to 90 - 100 PSI

Step 7: Check the Air Brake ABS System (If Applicable)

Step 8: Test Air Loss Rate

Step 9: Test Low Air Pressure Warning Device

Step 10: Check the Tractor Protection System

Step 11: Finalize paperwork, and provide the results to the driver (i.e. out-of-service, etc.)