Document E53d05eX8jZJ2v3vjex6pw6x

AMERICAN BRAKEBLOK DIVISION BULLETIN NO. 9 DON'T OVERLOOK THE BRAKE SHOES Truck, trailer and bus shoes represent costly items and are important to the safe operation of the brakes. All precautions should be taken to extend their life and ensure proper brake operation. Frequently heavy duty brakes are open with the brake shoes and their mechanisms exposed to road contamination. This contamination becomes particularly damaging during winter months where roads are liberally salted. The use of demountable dust shields during winter months will protect the brake shoes and mechanisms resulting in measurable benefits. INSPECTION: The condition of the brake shoes at time of reline merit close inspection. Should the shoe radius be off, any deformity in the shoe, broken welds or worn areas are ^sure to result in brake problems. A shoe fixture to accurately check a used shoe to new shoe specifications is advisable. In the absence of such a fixture or gauge, a new shoe length measure ment between cam and anchor centers will suffice to detect a sprung shoe. If the shoe is acceptable to this point the next step is to thoroughly clean the shoe prior to continuing the inspection. This includes cleaning the shoe table as well as the web. In some instances wire brushing is not adequate to clean the shoe down to bare metal. Rust flaking, which most frequently occurs on the shoe table as the result of moisture and contaminants held under the brake lining, can be removed by lightly tapping with a hammer. If rust flaking is very pre valent, consideration should be given to scrapping the shoe as this could weaken certain sections of the shoe, making it unfit for further service. After the shoe is thoroughly cleaned make a close inspection of the complete web and table junction area for any separations and broken welds. The cam and anchor ends of the shoe web should also be inspected for wear and peening (impacting) which would show deformation in these areas. This inspection should also include the flatness of the shoe table and its squareness with the web. The rivet or bolt holes in the shoe table must be closely inspected for any elongation or burring as both conditions will impair the proper attachment of lining. The new lining must fit tightly against the shoe table and be held firmly in place, otherwise brake noise can be expected and short lining life as well due to the material loosening up on the shoe table. SPNY 005975 SCF-ABEX-0038