The National Highway Traffic Safety Administration (NHTSA) Office of Defects Investigation is looking into incidents of reduced brake effectiveness leading to extended stopping distances in 2008 Mazda CX-9 vehicles.

The investigation was opened after data was submitted to NHTSA by Mazda, including reports of such incidents from 2008 and continuing into 2010. Mazda’s data showed a high number of warranty claims and reports for the service brakes.

In most instances, Mazda dealers identified the primary cause as an internal brake fluid leak from the master cylinder into the vacuum booster. When brake fluid leaks into the vacuum booster, the driver can experience reduced brake effectiveness, which can result in extended stopping distance. An evaluation is underway to assess the scope, frequency and safety consequences of the alleged defect.

Defect Investigations Results [NHTSA]