Document qm95nx7L9D4ba0MJmnZyp6qak

AMERICAN BRAKEBLOK DIVISION BULLETIN NO. 3 AUTOMATIC ADJUSTERS The trend is veering toward self-adjusted brakes in the truck and bus field. Acceptance of the self-adjustment brake feature in today's passenger cars, no doubt, prompted the interest. Maintenance cost, however, is encouraging the fleets to evaluate this time and cost saving device. The automatic slack adjuster for the cam brakes has been tested with many fleets. Its exposure to the elements did present some problems in the winter months with the road salt and contamination. This is not the case with the wedge type where the self-adjusting mechanism is enclosed within the drum and is thus free of external contamination. It is acknowledged that self-adjusters reduce maintenance cost. When the lining to drum clearance remains constant with minimum movement of components, the results are less air usage and, of course, better brake timing and balance. It is true that many fleets recently have removed the automatic slack adjusters because of problems of malfunctioning. This then should be our alert when checking lining mileages or when investigating any complaints that we inquire if the vehicles were equipped with automatic slack adjusters. As a word of caution, when early relines are reported you will learn upon investigation that often only the linings in one wheel were worn. This has been the case all too frequently on vehicles where the automatic slack adjusters were not functioning properly. Should a lining test program be inaugurated, be sure to confine the tests to vehicles without the automatic slack adjusters and thus remove the introduction of one possible variable. At this time there is interest and evaluation being given to automatic slack adjusters that are free of external linkage. A few makes of these automatic slack adjusters which have the adjustment enclosed in the unit and thus are free of external contamination are on test in some fleets. The reports of performance while encouraging are not conclusive at this time because of the limited service exposure. _ Patrick J. Meade Technical Service Engineer SPNY 005967 SCF-ABEX-0048