515050 Wheel Bearing Part Fitment Information 2002-2005 for Ford Explorer 4WD 2003-2005 for Lincoln Aviator 4WD RWD2002-2005 for Mercury Mountaineer 4WD RWD The importance of 515050 wheel bearings Hub assembly is a critical components, it allow the wheels to spin freely and at the desired speed.They’re also responsible for keeping the wheels attached to the vehicle.As the bearings begin to wear out or become damaged, they impact the wheels ability to spin smoothly, freely, and securely.When this happens your vehicle will become shaky, and your wheels will not be secure.