Table of Contents
What are the two purposes of slack adjuster?
The air brake slack adjusters perform two functions: (1) The slack adjuster acts as a lever arm to convert the linear pushrod force to rotational camshaft torque. The length of the slack adjuster determines the amount of torque multiplication provided from the pushrod.
What are the functions of a slack adjuster?
The Automatic Slack Adjuster (ASA) is a vital part of the foundation brake. It acts as a lever, forming the connection between the actuator and the camshaft. The function of the ASA is to compensate for wear in both brake lining and brake drum while maintaining a constant stroke of the actuator.
How do I know if my slack adjuster is bad?
Usually brakes locking up is s-cam or s-cam bushings. That’s fairly easy to check, with no brake pressure put a pry bar on the slack adjuster. If there’s any significant movement up down or back and forth (some in and out is fine) then everything needs to come apart.
What is slack adjuster mean?
Slack adjuster means a lever attached to the brake camshaft and connected to the brake chamber push rod. The slack adjuster provides a means of adjusting the brakes to compensate for brake lining wear.
Are there left and right slack adjusters?
Slack Adjusters There are two automatic slack adjuster designs: HANDED and UNHANDED. For most applications, install a handed automatic slack adjuster so that the pawl faces INBOARD on the vehicle. The pawl can be on either side or on the front of the slack adjuster housing.
At what PSI do air brakes lock up?
60 psi
If the pressure in the air system pulls below 60 psi, the parking brake knob will pop out and set the parking brakes. This is a safety feature so the truck will stop, because if the pressure falls too low, the service brakes will not work. The other system component stops the vehicle when you push on the brake pedal.
How often should slack adjusters be greased?
Every six months or 50,000 miles, grease the slack adjuster using an approved grease. The adjusters have a grease fitting to allow lubrication during normal chassis servicing.
How does a automatic slack adjuster work?
How Do Slack Adjusters Work? The slack adjuster assembly transmits the braking torque to the S-cam and facilitates the adjustment of clearance between the brake lining (brake pad) and the brake drum. So, when the driver presses down on the brake pedal, air is forced into the brake chamber and shoves the push rod out.
How can you check slack adjusters?
Measure the distance between the air cylinder and the chalk mark. If the measurement is at or less than 3/4 of an inch, it does not require adjustment. Anything over 3/4 of an inch means the slack adjuster should be adjusted. There is one pushrod for each brake assembly at each end of every axle so check each of them.
What do you need to know about slack adjusters?
but a lot are found to be out of adjustment during roadside brake inspections.
What are the slack adjusters?
On an air-brake system, the slack adjuster is what is used to adjust the brakes. It is located on the axle housing on the air canister near the wheel. On drum brakes, it’s between the pushrod and the S-cam. On disc brakes, it is between the pushrod and the power screw.
What is slack adjuster?
Slack adjusters (also called brake adjusters or just “slacks”) regulate the distance that the air brake has to travel to apply friction to the wheel. This distance increases as use of the brake causes the friction material of the brake shoe to wear away.