Picking up the slack with Diesel Technic
Components provider Diesel Technic has issued guidance on the topic of slack adjusters, and why regular inspection is critical to optimal performance.
“Mandatory on most trucks, trailers and passenger vehicles since 1995, automatic slack adjusters (ASAs) deliver reliable and consistent brake performance – and prevent the need for ongoing adjustment,” said Mark Todd of Diesel Technic.
“However, automatic doesn’t mean maintenance free.”
The slack adjuster is an arm attached to a push rod on the brake assembly, Mark explains.
“When the brake is applied, a rod pushes out on the slack adjuster, which turns the S-cam forcing the brake shoes apart to apply the necessary friction to slow the vehicle.
“As the brakes wear, the stroke changes and the slack adjuster is designed to compensate for brake lining and drum wear over time.
“Performing a slack adjustment means simply adjusting the push rod in the air chamber to within a predetermined tolerance, thereby maintaining optimal brake performance.”
Mark continued: “There are two basic types of ASAs, the more common Clearance Sensing or Stroke Sensing. It is a requirement that all ASAs are working correctly, so it is important to recognise the type and to know when the unit needs replacing.
“All ASAs are subject to wear and will need regular assessment – ideally at every inspection – and replacement as necessary.
“In addition to lubrication, which protects internal components and purges old grease, water and contaminants, checks include push rod travel, looking for cracks or bent control arm brackets and yokes, as well as broken bolts and signs of wear.”
Although they can be damaged by stones, speed bumps or kerbs, says Mark, it is important to note that an ASA out of adjustment is more often caused by a problem elsewhere in the vehicle’s braking system.
“Proper maintenance means no manual adjustment in service as it can cause premature wear on internal components,” he continued.
“In fact, it is more likely to mask an underlying issue that will lead to more serious problems down the road.
“Self-adjusting ASAs are quick and easy to install and are precision engineered.
“Made from the highest quality materials for wear resistance and operational safety, DT Spare Parts slack adjusters are particularly robust and low maintenance due to specially hardened areas and a cover protecting the mechanism against moisture, dirt and external influences.
“A special sealing construction and life lubrication ensures longer life for ASAs, a vital component in brake performance and efficiency of every vehicle.”
DT Spare Parts brand offers a complete range with more than 40,000 different spare parts for trucks, trailers, buses and vans, including all standard slack adjusters.
