NHTSA Preliminary Evaluation PE21003

The Office of Defects Investigation (ODI) opened this Preliminary Evaluation (PE) based on twenty-two (22) Vehicle Owner Questionnaires (VOQs) for soft rear brakes caused by air seeping into the rear brake lines of model year (MY) 2012-2020 Ducati Monster, Multistrada, SuperSport, Panigale, Scrambler and Diavel motorcycles.The consumers were alleging that the rear brakes would not properly function unless the rear brake pedal was applied several times or that there was a total loss of rear braking during normal applications, increasing the risk of a crash. In a March 2020 meeting, Ducati indicated that they were aware of certain models in which air may enter the motorcycles' rear braking system through the brake lines, due to exposure to heat from the exhaust system. Although this condition compromises rear braking performance, Ducati stated that they did not consider this to be a safety defect because the front and rear brake systems are hydraulically independent from each other, and a motorcycle's front brake system performs most of the stopping. Additionally, they believed that routine brake fluid replacement would resolve consumers' concerns, however complainants and dealership service technicians reported that, in some cases, after a dealer serviced the rear brake system, the rear brake pedal would feel soft and spongy again (indicating compromised brake performance) less than a year later--well before the recommended two-year brake fluid service interval. As a precaution, Ducati issued a series of technical service bulletins (TSBs) to replace the brake lines with redesigned ones, rerouting them away from the exhaust system.ODI's position is that all of the brakes on a motorcycle are considered necessary for safety. Analysis of the data identified that neither the entire model line nor the entire model year range of motorcycles covered by the investigation were affected, but rather certain sub-models or narrower model year ranges of motorcycles incorporated bra