With an automatic slack adjuster, you might periodically need to tighten it manually. It’s not a difficult procedure and you only need very basic tools to carry out this task.
Step 1 - Accessing the Slack Adjuster
Make sure the car is in park and have the other wheels blocked with chocks. Using your jack, raise the wheel to the point where you can turn it freely. You’ll need to use your service manual to know which type of slack adjuster your have. Once you know that, you’ll know what type of tool you need to adjust it.
Step 2 - Making the Adjustment
You now need to tighten the slack adjuster. Be aware that if turning it is difficult, you’re almost certainly turning it the wrong way. Expect a smooth movement. Keep on tightening until the brakes touch the drum and the wheel will no longer spin.
Loosen the slack adjuster very slightly; the wheel should still be hard to turn. Now, loosen it ¼ turn and see if the wheel will turn smoothly. If not, loosen a little more and try again. Keep going until the wheel will move freely. Lower the car off the jack to complete the adjustment of the slack adjuster.