Air brakes have in their construction slack adjusters. They help maintaining an even wear between the brake linings and they must be properly adjusted. The push rod connects the brake assembly to the arms of these devices.
Follow these steps:
- Park the vehicle and set the handbrake. Raise the car and put it on jack stands.
- With a piece of chalk, mark the spot where the push rod exits the air chamber.
- Take out the push rod and measure the distance between the chalk mark and the air chamber. If it’s more than ¾ of an inch the brakes need adjustment.
- Locate the slack adjuster bolt and rotate it with a screwdriver until you feel resistance. The correct direction to rotate the bolt is when the push rod extends outward.
- After that back off the bolt ¼ to ½ turn.
- Put back the push rod inside the air chamber.
- Your brakes should now be correctly adjusted.