Brakes grind, pulse or wear early

Nissan conducted safety recalls 08V-311 and 09V-431 to remedy leaking master cylinders on certain MY 2007 and 2008 Nissan Sentra vehicles.The recall populations were determined based on production changes to the master cylinder which were fully implemented into production on April 18, 2008.NHTSA utilized vehicle owner questionnaire (VOQ) reports and did not request field information from Nissan.ODI identified two MY 2008 Nissan Sentra VOQs including the petitioner?s vehicle, which were not covered by the recalls and reported a leaking master cylinder.Both of these incidents occurred 6 or more years into the service life of the vehicle.ODI also identified three VOQs which reported a leaking master cylinder after receiving the recall remedy.While one of these failures occurred within 36 months of the recall remedy, the other two occurred at a later time.ODI notes that the original recall addressed failures which occurred early in the life of the vehicle, typically during the first 36 months of service.Master cylinders are generally expected to experience wear and thus will display a finite service life.After a thorough review of the available data in NHTSA's VOQ database, the agency has not identified a trend that would call into question the scope or adequacy of Nissan's recalls.Accordingly, and in view of the need to allocate and prioritize NHTSA's limited resources to best accomplish the agency's safety mission, ODI is denying the petition.A detailed summary of ODI's analysi

On May 20, 2014, ODI opened PE14-014 based on eight complaints alleging incidents of excessive brake pedal travel in model year (MY) 2013 through 2014 Nissan Sentra, Versa Sedan and Versa Note passenger cars (Figure 1) and information in Early Warning Reporting field reports indicating issues with master cylinder internal seals.In response to an information request letter sent by ODI, Nissan identified a condition with the master cylinder in early production subject vehicles that could result in a slow internal leak past one of the recuperating seals to the brake reservoir when the brake pedal is depressed very slowly or lightly (Figure 2).The subject vehicles are equipped with fixed seal master cylinders supplied by TRW.To address concerns with water hammer noise with the standard seal design, the master cylinders in the early production subject vehicles used AWH (anti-water hammer) seals.The AWH seals are sensitive to contamination from assembly plant cleanliness issues, which can produce the internal leak condition during slow or light brake applies but perform as designed with normal or emergency brake applications.TRW indicated that the risk of contamination interacting with the subject seals is greatest after the evacuation and pressure fill process used to fill the brake system during the manufacturing process (early life issue).TRW developed a new master cylinder seal design (EVO seal) that addresses the noise concern and eliminates the internal leak concern associate