Press Release:

Transport Fleet Maintenance Tips
London, ON January 2010

Much has been written about automatic brake adjusters and whether or not they are capable of maintaining brake adjustment. So in our opinion at Freinmeister Group Inc, automatic brake adjusters will maintain shoe to drum clearance within DOT specifications, providing they are properly installed, lubricated, and in good working order and on brake chamber pushrods that were properly cut to length.

Automatic brake adjusters WILL NOT however adjust to make up for excessive brake wear of clevis yoke bushings, S-Cam bushings, worn s-cam splines of worn splines within the brake adjusters, chamber mount bracket deflection or brake drum deflection, to name a few issues.

Automatic brake adjusters should NOT be manually adjusted after the initial installation adjustment. Manually adjusting an ABA to correct a brake showing excessive brake stroke during roadside inspection will not fix the underlying problem, which is NOT shoe to drum clearance. The problem is excessive wear of brake parts that must be replaced.

NTSB (National Transportation Safety Board) in the USA has a bulletin out suggesting that ABA’s should NOT be manually adjusted after the initial installation or after a brake job or brake drum removal for service.

As a tradesperson involved in air brake maintenance, educating yourself to a “Best Practice” level is critical to your own safety and peace of mind. Read, listen and learn about both the Mark and Measure Test or the alternative Measure and Re-Measure Test. These two tests do not test automatic brake adjuster function, but do test overall condition of the S-Cam foundation brake. For specifics on fit, form and function of automatic brake adjusters, we suggest you visit the website of your chosen brand.

If you are looking for a helper to assist you with Mark & Measure Tests, see the BrakeBoss remote control tool elsewhere on this site as a helper for anyone with the responsibility to complete a Mark and Measure Test.