According to the NHTSA, these 7,697 2011 Kia Sorentos being recalled have rear disc brake calipers which may have been machined improperly. There is no detail as to what the machining defect may be but something is simple as a contact surface not being level enough could cause a minor leak of brake fluid. The vehicles affected were all produced between September 14, 2010 and October 4, 2010.
While brake fluid leaks like the one in the recent Kia Sorento recall may be a slow, gradual process, over time your braking system will become less responsive and less effective in stopping the vehicle. In addition to that, brake fluid is flammable so in a worst case situation, there is the (again, outside) chance of a fire. A leak like this usually shows itself first by the brake light in the instrument cluster lighting up but unfortunately, some people ignore those warning lights. Over time, the brake pedal will feel softer than before and should the problem be left alone long enough, the lack of fluid effectively removes the power assist feature of the braking system.
The NHTSA does not list a start date for this Kia recall but when letters go out, owners will be instructed to head to their friendly neighborhood Kia dealership where their rear brake assemblies will be inspected and any needed repairs will be made, free of charge.