SAE J160_202505

This document specifies a universal method of measuring the thickness change of friction materials to determine the effects of temperature. The test applies to both disc and drum-type linings commonly used in hydraulic and air brake systems for automotive or commercial vehicle applications. This document describes several methods for thermal swell and growth. Method A is where the friction material is in contact with a heated surface to simulate the heat input to the pad that occurs during actual usage. Method B uses an oven to heat the freestanding material and is an approximate procedure requiring less instrumentation. Method A is recommended for disc brake pad assemblies, noise insulators, or flat coupons, while Method B is recommended for curved drum brake linings. This document also describes how to test the warmed-up disc brake pads and noise insulators for hot compressibility using Method A. This revision recommends preconditioning per SAE J3281 to remove adsorbed moisture from the test specimen and specifies the procedure to measure hot compressibility for disc brake pads and noise insulators.

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