NHTSA Office of Defects Investigation
Preliminary Evaluation PE11-026: Brake master cylinder leak
- Closed
NHTSA's Office of Defects Investigation opened Preliminary Evaluation PE11-026 on August 9, 2011 and closed it on April 9, 2012. NHTSA's investigations file lists the 2008 Mazda CX-9 for it.
Updated daily from NHTSA's investigations file
Key facts
- NHTSA number
- PE11-026 (also written PE11026)
- 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 April 9, 2012
- Opened
- Closed
- Vehicle or equipment manufacturer
- Mazda Motor Corp.
- Component
- Service Brakes, Hydraulic — Foundation Components — Master Cylinder
- Vehicles and equipment
- 2008 Mazda CX-9
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 PE11-026.
The Office of Defects Investigation (ODI) opened PE11-026 to investigate possible brake performance loss due to brake fluid leaking from the master cylinder into the brake booster in model year (MY) 2008 Mazda CX-9 vehicles.
In response to ODI's information request letter, Mazda identified a problem with the manufacturing process for the master cylinder primary plunger that could result in inappropriate surface finish.
ODI's analysis of complaints and field reports determined that the problem was isolated to several months late in the production of the MY 2008 CX-9 vehicles.
Mazda indicated that changes to the plunger machining and inspection processes were incorporated late in MY 2008 vehicle production (June 25, 2008).
There are no confirmed failures related to the condition in subsequent production.
The subject master cylinder was used by Mazda in MY 2007 through MY 2011 CX-9 vehicles (approximately 132,000 vehicles) with no other significant problems related to master cylinder leakage.
ODI's analysis identified a total of 248 complaints and field reports potentially related to the subject condition in MY 2008 CX-9 vehicles.
The majority of the records reported that brake malfunction indicator lamp (MIL) illumination was the only symptom of a problem, with only 4% (9 reports) alleging any symptoms related to brake pedal feel or effectiveness.
ODI identified no crash claims related to the alleged defect.
In addition, analysis of this data showed a declining trend with 90 percent of the incidents reported before January 2011.
Based on the extremely slow leak rate associated with the alleged defect, the declining failure trend and the low probability that the condition would affect brake performance, this investigation is closed.
The ODI reports cited above can be viewed at www-odi.nhtsa.dot.gov/owners/SearchNHTSAID under the following identification numbers (ODI Nos.): 10442322, 10419837, 10449109
Vehicles and equipment listed for this investigation
NHTSA's investigations file lists these vehicles and equipment for Preliminary Evaluation PE11-026. 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.
Mazda
Mazda CX-9
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.
Mazda VIN check: decode a VIN to see its year, make and model.
Sources
NHTSA's investigation record for PE11-026
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.