The National Transportation Safety Board has issued a safety recommendations to the Federal Motor Carrier Safety Administration regarding automatic slack adjusters.

The board urges the FMCSA to work with the Commercial Vehicle Safety Alliance to develop and add to the North American Standard Inspection training materials a module that emphasizes the danger of manually adjusting automatic slack adjusters.
It suggests such work should not be done, except during installation or in an emergency to move the vehicle to a repair facility.
The board said manual adjustment of this brake component “(1) fails to address the true reason why the brakes are not maintaining adjustment, giving the operator a false sense of security about the effectiveness of the brakes, which are likely to go out of adjustment again soon, and (2) causes abnormal wear to the internal adjusting mechanism for most automatic slack adjusters, which may lead to failure of this brake component. (H-06-1)”
The panel also suggests drivers of commercial vehicles that weigh less than 26,000 pounds equipped with air brakes to undergo training and testing to demonstrate proficiency in the inspection and operation of air-braked vehicles. The training should emphasize that manually adjusting automatic slack adjusters is dangerous and should not be done, except during installation or in an emergency to move the vehicle to a repair facility.
The complete recommendation letter is available on the web at www.ntsb.gov/recs/letters/2006/A06_7_11.pdf.