Four Tests for Consistency of Automotive Brake Linings

Automotive brake lining is a complex composite of organic resin binder, asbestos fiber reinforcement, and friction modifying fillers. Laboratory and vehicle tests used to select and qualify specific formulations are time consuming and not generally suitable for quality control. A new integrated system of tests is therefore proposed. The tests are X-ray radiography and optical resinography for structural definition; thermal analysis for chemical composition and state of cure; and a short sliding friction (drag) test utilizing the widely available SAE J661 friction materials test machine. The tests are described in detail and typical results are presented.