[Cymbrogi]

I'm an absolute beginner when it comes to things mechanical, so please excuse me asking about what might seem like common knowledge to most of you: I took my '66 for PA state inspection and it failed from needing to have "lower arn bushings" replaced. Both places I took it to said this is an expensive repair job. And if the brake lines are rusted, it could be worse. Please, would someone explain to me what bushings are and why I should pay over 500.00 to replace them?