2007 Sterling L-Line Recalls

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.

ODI opened this preliminary evaluation based on a fleet report that it had experienced multiple wheel-end fires.The fleet believed this was due to the power spring fracturing and subsequently puncturing the diaphragm resulting in an air loss causing the brakes to drag.A vehicle driver suffered smoke inhalation during one of the fires suspected to have been caused by the alleged defect.Another injury was sustained by a mechanic when he attempted to remove the brake chamber with a broken power spring.The brake chamber sprung from its mounting bracket and struck the mechanic in the face, causing multiple lacerations.Brake chambers have a limited life span and are subject to wear out.However, the failures identified by the fleet are much earlier than expected and may not exhibit discernible failure symptoms.ODI initiated testing at the Vehicle Research and Test Center (VRTC) to determine the cause of the spring failure and to better understand any warning signs that may be present.VRTC's testing is ongoing as is Haldex's inspection of failed chambers returned from the fleet.This PE has been upgraded to an Engineering Analysis (EA11-011) to further evaluate the cause of the fires and assess the scope, frequency, and safety consequences of the alleged defect.

ODI gathered information from four auto hauler fleets during its investigation.At least five of the fleets' vehicles were damaged or completely destroyed by a fire caused by a leak in low pressure fuel line.The fleets reported numerous other failures that spilled large quantities of diesel fuel on roadways and disabled tractor trailers.Daimler Trucks North America submitteda recall notice on 24 February 2011.Daimler's announcement of a safety recall on this matter addresses ODI's concerns.The 573 letter was received prior to the due date of the IR response, therefore Daimler has been relieved from having to submit an IR response.Daimler will replace the upper and lower low pressure fuel lines with a more robust line.The exact remedy and replacement parts are not yet finalized.Daimler will be submitting a supplemental report when the information is available.ODI will closely monitor the remedy to ensure it is adequate.The subject vehicles have been recalled, therefore this investigation is closed.

ON NOVEMBER 19, 2007, FREIGHTLINER FILED DEFECT REPORT 07V-530 WHICH OUTLINES A SAFETY RECALL PROGRAM TO NOTIFY THE AFFECTED OWNERS AND CORRECT THE AFFECTED VEHICLES.