ford mustang axle question

Yikes! Now you got me spooked! I have 18" wheels on my 02 Mustang GT & I have heard that they can be hard on bearings & such, but there's no sign of excess heat on those parts. It is a little suspicious that you had just performed some brake work, Try "Mustangforums.com" there's alot of smart Mustang guys there, who may have seen this before.