Four Steps to Safer Braking

When it comes to your brakes, most people take them for granted that they will always work and sometimes that is just not the case. In the last twenty years, new vehicles are required to have self-adjusting brakes (S-ABAs). And although they have been around for twenty years, people seem to not understand how they work and are under the misconception that automatic slack adjusters will never go out of adjustment. Unfortunately, this is not the case.  

Over time, slack adjusters do go out of adjustment. This can be due to use or just because of the length of time they have been in service. Because these changes might not be noticed on day-to-day drives, it is critical to check your brakes before every single trip. If your stopping power is reduced too much, you will get cited/fined when you get inspected.  The federal reduced stopping distance regulations are in place to protect you and other drivers.

If you discover that your S-ABAs are out of adjustment, please do not try to adjust them yourself as this is the most ticketed item in DOT inspections. In these inspections, the brake chamber pushrod stroke is measured down to 1/8 of an inch, so the risk is not worth it.

However, it is a simple procedure to measure the pushrod stroke. You will need the following items to complete this small task: Chalk to mark the pushrods, protective eyewear, ruler, flashlight, pencil and paper, someone to assist you and a little time. You then want to follow these 4 steps:

1. Park your vehicle in a safe spot and make sure you have chocked the wheels.  Release the spring brake and make sure your psi pressure in the air brake reservoir is 90-100. Do this while the vehicle is running.
2. Manually inspect each brake to verify it is in the normal release position and you cannot visually see any issues. Mark each pushrod with the chalk to confirm the starting location where the pushrod exits the brake chamber.
3. Push your brake pedal down until it stops. Have your helper measure the distance each pushrod has stroked and record this. Make sure your pressure does not drop below 90 psi. If this happens, stop testing for a moment or two to allow the pressure to build back up.
4. Compare the regulation stroke limit with the numbers you compiled and if there are any measurements that are near or under the regulation limit, then you know it is time to have your brake components serviced immediately. 

Be sure to remember that if anything feels off with your brakes, you can always contact your local Volvo Truck dealership to conduct a brake system check. Our certified technicians have the latest information regarding stroke limits and will be happy to help.

Need to purchase Slack Adjusters for your truck?  Check out our selection.