DIMINISHED BRAKING

What NHTSA is examining

Odi has reviewed complaint and background investigation information received from component suppliers (1) haldex and (2) meritor wabco and the principally-affected vehicle manufacturers.this information indicates that the seal material in certain air brake relay valves manufactured by haldex and distributed by meritor wabco may degrade prematurely and affect the valvefunction resulting in diminished vehicle braking performance (increased stopping distance).haldex and meritor wabco investigations have associated the degraded seal condition with exposure to aerosol oil that has migrated through the air compressor and into the brake system.these companies maintain that changes in diesel engines and lubricants adopted to conform to increasingly stringent epa emissions requirements have created an adverse operating environment for the control valve as well asother brake system components.odi observes that vehicle manufacturers are responsible for assessing changes in vehicle operating environments and the effects of these changes on the components that are integrated into their vehicle system and that vehicle manufacturers are responsible for specifying components that will function safely and reliably when integrated into the various vehicle systems.odi also observes that the component design should anticipate adverse environments and incorporate designs that will assure that a failure of an affected component will be detected through reasonable maintenance surveillance before…

Vehicles under investigation