NHTSA Office of Defects Investigation
Preliminary Evaluation PE14-027: Front brake hose failure
- Closed
NHTSA's Office of Defects Investigation opened Preliminary Evaluation PE14-027 on August 22, 2014 and closed it on February 3, 2015. NHTSA's investigations file lists the 2013 Ford Explorer for it.
Updated daily from NHTSA's investigations file
Key facts
- NHTSA number
- PE14-027 (also written PE14027)
- Investigation type
- Preliminary Evaluation The first stage of most defect investigations: NHTSA's Office of Defects Investigation gathers basic information about a possible safety defect, including from the manufacturer.
- Status
- Closed February 3, 2015
- Opened
- Closed
- Vehicle or equipment manufacturer
- Ford Motor Company
- Component
- Service Brakes, Hydraulic — Foundation Components — Hoses, Lines/Piping, and Fittings
- Vehicles and equipment
- 2013 Ford Explorer
A recall appears here only when NHTSA's investigations file links one to the investigation; NHTSA's summary or record can name others.
NHTSA's summary
As NHTSA's Office of Defects Investigation wrote it for Preliminary Evaluation PE14-027.
try.vin does not copy NHTSA's investigation documents; NHTSA's investigation record lists the ones NHTSA has published.
The Office of Defects Investigation (ODI) opened PE14-027 based on a report of 13 front brake hose (jounce hose) failures in 11 vehicles in the District of Columbia Metropolitan Police Department (DCMPD) fleet of 46 model year (MY) 2013 Ford Explorer Police Interceptor (PI) vehicles (VOQ 10621634).
The DCMPD fleet provided Ford with 71 jounce hoses for analysis, including 4 of the 13 failed hoses.
Inspection of each of the failed hoses identified a small tear in the outer cover on the body end of the hoses on the outboard side. Ford?s lab analysis of these hoses identified splits in the inner liners 1.5-2.0mm from the end of the nipple (outside of the crimped ferrule joint).
Ford conducted pressure testing of 10 randomly selected samples of the remaining 67 hoses that had not experienced leaks and 9 of the samples leaked at 6,000 psi.
Ford?s examination of the 9 hoses that leaked in the pressure tests found 4 that failed on the outboard side of the hose (similar to the 4 leaking field parts) and 5 that failed on the body end of the hose on the inboard side.
Four additional non-leaking hoses were sent to the hose supplier, Hitachi, for analysis.
Broken yarn was observed in scanning electron microscope examinations at both the body side and caliper side hose to ferrule crimps, indicating severe bending stress had occurred at these locations. Hitachi supplied an additional set of non-leaking field return hoses and a brand new set of hoses to an outside laboratory (Element Materials Technology) for analysis.
The lab did not identify any manufacturing or material deficiencies in the hoses and concluded that the hose failures were caused by excessive bending stresses.
Based on the examinations of the returned jounce hoses, Ford conducted durability testing on new hoses that were the same design as those found on the subject vehicles.
Ford first determined the worst case conditions for the hoses; jounce bumpers removed, internal rebound stops fully compressed, and shock absorbers attached. With the jounce hose installed, the steering was rotated to the maximum turn angle while the suspension was translated from full jounce to full rebound.
This determined the maximum hose length of 13.0in (331mm) and a minimum hose bending radius of 1.6in (40mm).
Using these conditions hoses tested on a Suspension Motion Simulator far surpassed Ford?s performance specifications. Twenty (20) complaints of front brake jounce hose failure were identified on a total of 18 Explorer PI vehicles, including the 13 hose failures in 11 vehicles from the DCMPD fleet that prompted PE14-027.
The remaining 7 complaints included 3 from one fleet that reportedly occurred on the banjo block end of the hose assembly and single complaints from 4 other fleets.
Only two brake hose assemblies were used in the subject and peer Explorer vehicles, with the BB53 level hose used until June 20, 2012, and an updated DB53 level hose used thereafter.
No pattern of failures was observed by hose assembly, with 15 of failures involving the BB53 hose assembly (including the 13 from DCMPD manufactured in March 2012) and 5 the DB53 hose assembly built after June 20, 2012. No root cause was determined for the reported Explorer PI jounce hose failures, but Ford identified improper service repair procedures (e.g., hanging the brake caliper from the brake hose during brake pad replacement) as a possible contributor to higher than expected rate of front brake jounce hose leaks. ODI?s analysis of field data, hose inspection and test data did not identify evidence of any defects in hose material, manufacture or vehicle installation.
The closing of this invest
Vehicles and equipment listed for this investigation
NHTSA's investigations file lists these vehicles and equipment for Preliminary Evaluation PE14-027. A listed model year means only that an investigation names it; it says nothing about any particular vehicle. Model years with a try.vin recall page link to that page's NHTSA investigations section.
Ford
Ford Explorer
What an NHTSA investigation is
NHTSA's Office of Defects Investigation (ODI) looks into possible safety defects in vehicles and equipment, often after owner complaints. An investigation usually starts as a Preliminary Evaluation, or as a Recall Query when it concerns whether an existing recall covers the right vehicles or fixes the problem, and ODI can upgrade it to a more detailed Engineering Analysis. A Defect Petition asks NHTSA to open an investigation, and Audit and Equipment Queries are administrative investigations into whether companies complied with federal vehicle safety requirements, such as reporting, recall and certification rules.
An open investigation is not a finding that a safety defect exists, and NHTSA can close one without a recall.
To see whether a specific vehicle has an open recall, enter its VIN at nhtsa.gov/recalls.
Ford VIN check: decode a VIN to see its year, make and model.
Sources
NHTSA's investigation record for PE14-027
Investigation details come from NHTSA's investigations file, which try.vin imports once a day. The investigation types are described from the U.S. Department of Transportation Inspector General's May 2023 report on NHTSA's Office of Defects Investigation, NHTSA's petition rules (49 CFR Parts 552 and 557) and NHTSA's Office of Defects Investigation procedures. How try.vin reads NHTSA investigations.