1999 Mercedes-Benz ML320
4 Defect Investigations from the NHTSA
NHTSA Defect Investigations for the 1999 Mercedes-Benz ML320
The Office of Defects Investigations (ODI) is an office within the NHTSA which investigates serious safety problems in the design, construction or performance of vehicles. The NHTSA is authorized to order manufacturers to recall and repair vehicles, if the ODI finds a safety issue. NHTSA investigations for the 1999 Mercedes-Benz ML320, both ongoing and closed, are listed below:
INVESTIGATION: ENGINE CRANKSHAFT PULLEY FAILURE
NHTSA Preliminary Evaluation #PE03058
Component(s): Engine And Engine Cooling:Engine:Gasoline:Belts And Associated Pulleys
Summary: The Office Of Defects Investigation (ODI) opened this preliminary evaluation to investigate allegations of engine crankshaft pulley harmonic balancer failure that could result in loss of power-steering assist.ODI has received a total of 546 non-duplicative reports that allege engine crankshaft pulley harmonic balancer failure on all Mercedes-Benz vehicles using the subject component.the subject component failures are progressive in nature and only a small percentage of the complaints and warrant claims involved a failure that had progressed far enough to effect power steering performance (6 of 55 ODI complaints reference increased steering effort).there have been no crashes or injuries related to the alleged defect.a safety-related defect has not been identified at this time and further use of Agency resources does not appear to be warranted.accordingly, this investigation is closed.the closing of this investigation does not constitute a finding by NHTSA that a safety-related defect does not exist.the Agency will take further action if warranted by the circumstances.see summary report attached for further detail.
INVESTIGATION: BRAKE LINE CHAFE
NHTSA Engineering Analysis #EA08009
Component(s): Fuel System, Gasoline:Delivery:Hoses, Lines/Piping, And Fittings
Service Brakes, Hydraulic:Foundation Components:Hoses, Lines/Piping, And Fittings
Summary: Analysis of complaints to ODI and Mercedes and warranty claim data submitted by Mercedes indicates that the alleged defect has occurred at a low rate (36.5 complaints per 100,000 vehicles and 0.29 percent warranty claim rate), with no discernable defect trend indicating that the rate of chafing related brake line failures is increasing.there have been no new complaints since January 2009.when the analysis is limited to incidents of brake line leakage that resulted in allegations of reduced brake effectiveness, the rate drops even further (22.3 complaints per 100,000 vehicles and 0.04 percent warranty claim rate). Mercedes provided data showing that in the rare instances when chafing did progress to brake line leakage the driver would be immediately alerted to a problem by illumination of the bright yellow "esp/bas" warning lamp and changes in brake pedal feel.continued operation with a leaking brake line would result in illumination of the bright red "brake" warning lamp and an audible chime due to low master cylinder reservoir level. Continued operation with the brake warning lamp illuminated would ultimately drain the reservoir for the affected circuit, resulting in loss of the circuit and an approximately 80% increase in stopping distances. Surveys conducted by ODI and VRTC indicate that routing anomalies may be more common than the complaint and warranty data suggest for the subject line bundle, with line contact or other routing anomaly noted in 13 of 51 vehicles surveyed by ODI and VRTC (25.5%).while evidence of contact between the fuel line and subject brake in a particular vehicle is not necessarily predictive of eventual line failure/leakage, significant chafing wear was noted in two survey vehicles (3.9%).to address concerns with line routing and ensure that lines with evident chafing do not progress to a leak condition, Mercedes will conduct an owner notification program instructing owners to bring the vehicles to a dealer for a free inspection and repair.lines that do not have a spacer (rubber grommet or omega-clip) between the subject fuel and brake lines will have an omega-clip spacer installed to ensure adequate clearance between the lines.brake lines with chafe marks will be replaced. Accordingly, this investigation has been closed. The closing of this investigation does not constitute a finding by NHTSA that a safety-related defect does not exist. The Agency will continue to monitor complaints and other information relating to the alleged defect in the subject vehicles and take further action in the future if warranted. For additional information regarding this engineering analysis refer to the EA08-009 closing report.
INVESTIGATION: POWER STEERING HOSE LEAK
NHTSA Defect Investigation #RQ08002
Component(s): Steering:Hydraulic Power Assist System
Steering:Hydraulic Power Assist:Hose, Piping, And Connections
Steering:Hydraulic Power Assist:Power Steering Fluid
Summary: Mercedes-Benz usa (mbusa) will notify certain model year (MY) 1998 through 2003 M-class owners of the need to bring their vehicles into dealers to address the issue previously campaigned under mbusa recall 2003-040005 (NHTSA recall 03V-121).the mbusa campaign, which ODI is designating recall 08V-465, will replace the power steering cooler hose and clamp in all vehicles that received the original recall remedy for 03V-121 and which haven't received a subsequent repair to install a revised hose and clamp.approximately one-third of the vehicles that received the original repair procedure and parts returned for subsequent service for leakage from the hose fitting and, in approximately 10 percent of these vehicles, complete separation of the hose from the cooler.a revised service procedure for 03V-121, which involved replacing the old hose and clamp with modified parts, had significantly lower rates of return repairs.mbusa will apply the revised service procedure from 03V-121 to the vehicles covered under 08V-465.accordingly this recall query is closed.
INVESTIGATION: POWER STEERING HOSE ASSEMBLY LEAKAGE
NHTSA Preliminary Evaluation #PE03006
Component(s): Steering:Hydraulic Power Assist:Hose, Piping, And Connections
Steering:Hydraulic Power Assist:Power Steering Fluid
Summary: The hose clamp used to secure the power steering fluid cooling hose to the steering fluid cooler may not provide sufficient clamping force for the connection.the loss of power steering fluid may result in gradual reduction in power steering assist (I.e., increased steering effort) over time, with potential damage to the power steering pump. There have also been a few incidents of hose separation from the fitting, that have resulted in more rapid reductions of power steering.testing conducted by Mercedes-Benz indicates that the leaked fluid is not likely to be exposed to hot engine components.there are no known allegations that the defect condition has caused a vehicle fire. Mercedes-Benz will conduct a voluntary recall campaign for the subject M-class vehicles.Mercedes-Benz will install a new hose clamp on the power steering hose to the power steering cooler of the subject vehicles.during clamp replacement, the power steering cooling hose will be inspected and replaced as necessary.