NHTSA Office of Defects Investigation
Engineering Analysis EA11-011: Haldex Spring Brake Failures
- Closed
NHTSA's Office of Defects Investigation opened Engineering Analysis EA11-011 on September 9, 2011 and closed it on September 25, 2013. NHTSA's investigations file lists the 2007 Sterling L-Line for it.
Updated daily from NHTSA's investigations file
Key facts
- NHTSA number
- EA11-011 (also written EA11011)
- Investigation type
- Engineering Analysis A more detailed stage of a defect investigation, opened when NHTSA's Office of Defects Investigation decides an issue merits further review, often after a Preliminary Evaluation or a Recall Query; it can include vehicle testing, surveys and further information requests.
- Status
- Closed September 25, 2013
- Opened
- Closed
- Vehicle or equipment manufacturers
- Daimler Trucks North America, LLC; FREIGHTLINER LLC
- Components
- Parking Brake — Conventional — Air; Service Brakes, Air
- Vehicles and equipment
- 2007 Sterling L-Line
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 Engineering Analysis EA11-011.
try.vin does not copy NHTSA's investigation documents; NHTSA's investigation record lists the ones NHTSA has published.
ODI opened a Preliminary Evaluation (PE11-007) based on one fleet report alleging it had experienced multiple wheel-end fires involving the subject vehicles.
The fleet believed the fires were due to a power spring fracturing and puncturing a brake chamber diaphragm resulting in a loss of compressed air to the brakes.
The loss of air was believed to cause the brakes to drag and overheat.
ODI upgraded PE11-007 to this engineering analysis to further evaluate the cause of the wheel fires and assess the scope, frequency, and safety consequences of the alleged defect.
After a comprehensive review of the data related to brake chamber failures or replacements on the subject vehicles, ODI did not identify the existence of a safety related defect trend.
Of the two vehicle fires initially reported, only one was subjected to a fire investigation.
The fire investigator in that case could not identify the component responsible for the vehicle fire.
Driver statements reviewed from one fleet which experienced two brake overheating events indicated that the vehicles had not been operating at normal air system pressure levels prior to the events.
In addition, the failed or replaced chambers had been in service on average nearly 50 months.
ODI reviewed 477 warranty claims and fleet reports of brake chamber failure or replacement.
From the data review, three (3) brake overheating incidents involving a subject size 24/30 failed brake chamber were identified.
In reviewing the time in service for the overheating incidents, it was found that vehicles had an average of 50 months in service.
This time in service represents a typical service life wear out.
The injuries reported in the opening resume for this investigation are no longer being considered as having resulted from the alleged defect in the subject brake chambers.
In the case of the smoke inhalation originally reported, the fire was not determined to have been caused by a failed brake chamber.
In the case of the injuries that resulted while replacing a subject brake chamber, it was found that these chambers have a limited service life and are subject to wear out.
As a result, brake chambers are replaced frequently and standard safety precautions should be followed during this maintenance procedure that would prevent any chamber being replaced from experiencing an uncontrolled release of the compressed spring.
DTNA has informed NHTSA that it will take the following action to further reduce the likelihood of subject component failures.
DTNA will offer owners of subject vehicles, equipped with the original size 211/212 chambers, a free replacement of the chambers.
The chambers will be replaced with the more robust 003/004 sealed chambers.
In light of the low rate of wheel end fires resulting from a premature failure of the power spring in the subject vehicles, and DTNA's actions to reduce the likelihood of a failed brake chamber, further use of agency resources does not appear to be warranted.
The closing of this investigation does not constitute a finding by NHTSA that no safety-related defect exists.
The agency reserves the right to take further action if warranted by the circumstances.
For additional information, see the attached closing report.
Vehicles and equipment listed for this investigation
NHTSA's investigations file lists these vehicles and equipment for Engineering Analysis EA11-011. 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.
Sterling
Sterling L-Line
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.
Free VIN check: decode a VIN to see its year, make and model.
Sources
NHTSA's investigation record for EA11-011
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.