NTSB warns of Haldex slack adjuster failure

WASHINGTON, D.C. (April 2, 2001) — The U.S. National Transportation Safety Board has issued advisory bulletins to other federal agencies, trucking associations, fleet operators and commercial vehicle safety inspectors to inspect automatic slack adjusters made by Haldex Brake Products Corp.

The NTSB warned that the control arm may fracture or come loose from the ASA itself. The agency said operators of vehicles with Haldex automatic slack adjusters should thoroughly check each one for cracks and fractures, and to make sure the ASA is working properly and brakes are in proper adjustment.

The NTSB has no regulatory or enforcement authority and can only make recommendations as a result of the accidents it investigates. The warning stems from NTSB’s investigation of a 1998 bus accident. While NTSB said brake performance did not cause the accident, investigators found the right-side brake “grossly out of adjustment” but the left side in proper adjustment. The investigators said a control arm on the ASA had fractured, apparently long before the accident, and had gone undetected even when the bus had been inspected three days before the crash.