The power steering rack developed a leak causing the oil pressure to the unit to fail resulting in loss of power steering function. this vehicle dose not have a warning system to alert the driver of this type of failure. a previous safety recall was issued january 2009 (safety recall #2008-120011) for 2008 ml 320's for a defect such as this. however, this particular vehicle was not part of that recall. we feel this part should last the life of the vehicle without failure.