Mercedes recalls vehicles with defective parking brakes


Montvale, N.J. – July 16, 2017 – Mercedes-Benz USA has recalled more than 5,000 vehicles possibly equipped with defective parking brake components, according to documentation filed with the National Highway Transportation Association. The campaign affects 2016 Smart Fortwo compact cars manufactured between June 16, 2015 and Aug. 12, 2016. Mercedes estimated that 1 percent of the total number of vehicles named in the recall contain the defective parts.

The Defect

The vehicles referenced in the campaign could contain bowden cables with defective lock nuts, which may loosen over time and result in an increase in parking brake lever travel. The holding force of the parking brake might decrease as a result. This presents a serious safety hazard for owners, especially those who regularly park their vehicles on inclines and engage the parking brake. However, Mercedes-Benz has not received any field reports connecting the defect to accidents or injuries.

Timeline of Events

Daimler Automotive Group, which owns Mercedes-Benz, received a field report in mid-2016 that summarized an instance in which the parking brake on a customer’s vehicle failed to engage properly. The company immediately initiated a root-cause investigation to understand the cause of this mishap and ascertain whether a more widespread mechanical issue existed. Engineers involved in the inquiry immediately pinpointed a problem with the lock nut on the bowden cable. DAG then contacted its suppliers to identify possible fabrication issues.

In late 2016, the DAG team investigating the defect discovered that installation of the parking brake during the assembly process may have affected the microencapsulation process, resulting in lock nut hardware prone to slippage. During the opening months of 2017, the car company tested the affects of the defective lock nut assembly. In April, engineers performed additional tests, this time assessing how the feature stood up to vehicle vibrations. Two months later, DAG engineers were able to replicate the original customer complaint via multiple parking brake lever application and release. The automaker then reviewed manufacturing records to determine what vehicles might contain the defect.

In July 2017, DAG decided that the defect presented a serious safety risk to owners and launched a recall campaign. The organization notified dealers soon after.

The Solution

DAG has ordered dealers to replace the lock nuts in affected vehicles free of charge, according to additional documentation submitted to the NHTSA. The repairs are covered under existing new car warranties and therefore are not subject to official reimbursement plans. Owners should expect to receive notification in September. Those in need of more immediate assistance can contact Smart customer service at (877) 496-3691. They can also reach out to the NHTSA directly through its Vehicle Safety Hotline at (888) 327-4236.

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