What Is a Slack Adjuster?

A slack adjuster is a part of a truck's brake system. It adjusts the force exerted on a brake shoe to compensate for wear and tear. The slack adjuster is located in a space between the back wheels and the brake drum. It is a mechanical device that turns a s-cam that pushes the brake shoe apart. This force applies braking pressure to the truck, allowing the truck to stop.

There are two types of slack adjusters: manual and automatic. Manual slack adjusters compensate for the distance between the brake chamber push rod and the slack adjuster, while automatic ones remove slack from the brake linkage. The slack adjuster is an important part of the air brake system in heavy-duty trucks.

The demand for slack adjusters is directly related to the volume of vehicles sold in North America. The region accounts for the second-largest share of the commercial vehicle market in terms of volume. Therefore, slack adjuster demand is expected to grow rapidly in the coming years.

Automatic slack adjusters come with a protective cap that must be removed prior to adjustment. This cap is essential to protect the adjuster mechanism from contaminants. Some manufacturers design their slack adjusters to never require manual adjustment in service. However, some drivers may have a problem with their vehicle's brakes that require manual adjustment.