The 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., Kansas City, Mo.

At issue is the ASA's control arm, which the NTSB says may fracture or come loose from the ASA itself. Should this happen, the ASA stops adjusting the brake. The NTSB report uses the term "deadjust," implying that brake adjustment actually backs off.
NTSB's concern grew out of its investigation of a fatal bus accident near Atlantic City, N.J., on Christmas Eve 1998 in which eight passengers were killed. While the NTSB said brake performance did not cause the accident, its 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 quite a while before the accident, and had gone undetected even when the bus had been inspected three days before the crash.
The NTSB is calling for operators of vehicles with Haldex automatic slack adjusters to thoroughly check each one, looking for cracks and fractures and to make sure the ASA is working properly and brakes are in proper adjustment.
Haldex officials told TruckingInfo.com yesterday that they had just received the NTSB notification and would have no comment until they file their reply to the NTSB.
The NTSB has no regulatory or enforcement authority and can only make recommendations as a result of the accidents it investigates.