How does dealer know lower left/right control arms broken if bushings sealed ?

bushings are only a part of the control arms. there may be other areas that are damaged. if you dont believe them, get a second opinion from another shop and a bid from them to compare. Roy

Trained automotive technicians are experts. Thats how we know.

A visual determination would have been made on the leaking struts, As there would be a visual trace running down body of shock/strut. As far as the control arm bushings, we at this shop have seen numerous vehicles that the arm bushings just are worn. They are not a sealed bushing, and any inspecting shop should be able to notate if that issue is present. (if the issue IS present) The dealers use "cheap services" to lure customers for service, due to thats how dealers make money.