How to Adjust an Automatic Slack Adjuster

Our mechanic takes a look at how to adjust an automatic slack adjuster on a Hendrickson Air Ride suspension system. He covers the basic methods to adjust as well as checking the functionality of the slack adjuster. For more information on service or repairs please contact one of our locations or visit our website www.badger-utility.com

Hi, I am Aaron with Badger Utility, and I am going to show you how to adjust automatic slack adjusters and check their functionality. Having properly adjusted automatic slack adjusters not only maintains even brake wear, but also maintains the proper stopping distance.

This is an automatic slack adjuster. It maintains proper brake adjustment on the wheel end. What we will do to adjust this is put our wrench on here and turn it clockwise until the brake tightens up. Then we will back it off one half turn, and your brakes should be set in the proper adjustment.

Now let's make sure the brake adjuster is working properly. What we will do is back it off further than one half turn. This brake adjuster is already backed off one half of a turn. Then we will take a wrench and put it on the adjust nut and apply the brakes.
Release, Apply, Release, Apply, Release, Apply, Release.
As you can see the wrench is turning. That means the brake is trying to adjust itself back up under application.

Adjusting an automatic slack adjuster is fairly simple. Making sure that all four wheel ends are adjusted properly will keep your trailer stopping as it should.