NHTSA steps up Ford Police Interceptor SUV brake failure inquiry
The agency has opened an engineering analysis to determine if the failures warrant a recall.
The National Highway Traffic Safety Administration has reopened an investigation into brake-hose failures with Ford's Police Interceptor Utility.
The City of Sacramento police fleet had reported seven front brake-hose failures in five different Interceptor SUVs, all occurring during intensive Emergency Vehicle Operation Course (EVOC) training with evasive maneuvers and mock pursuits.
"Most of the failures resulted in a sudden loss of braking performance that caused the vehicle to run off the intended course," the investigation summary notes.
The NHTSA initially failed to identify any evidence of a defect in the hose material. A lab blamed the failures on excessive bending stress, and Ford suggested improper service procedures, such as hanging the brake caliper from the brake hose during pad replacement, could have contributed to the problems.
All five affected vehicles in the Sacramento fleet were repaired with a hose from the 2016-model-year Explorer, which includes a short steel tube attached to the caliper-end banjo fitting. Ford reported two additional failures in other fleets, however, including one involving a Sacramento Regional Transit vehicle that was driving on public roads at the time.
The company took a second look at the problems and determined that the hoses failed due to excessive temperatures produced during "hot soak" cycles, when the SUVs have completed a rigorous EVOC test and then parked without first allowing the brake components to cool.
"Ford believes that the excessive temperatures experienced at the crimp fitting in the subject vehicles are unique to the EVOC duty cycle, have not been observed in the standard on-road severe duty cycle testing performed by Ford and police fleets who routinely conduct such testing and are not likely to occur in service usage for on-road Explorer Police Interceptor vehicles," the investigation adds.
The NHTSA will now conduct its own engineering analysis to determine if a recall is warranted. The hose assemblies used in the Police Interceptors are said to be similar in design to the parts used on the 2013-2014 Explorer civilian vehicles, suggesting a recall could involve more than just law-enforcement vehicles.