Leaf Springs Going Bad?

How can you tell if your leaf springs are bad? I have a 95 Tercel with 165,XXX miles on it. When I go over a bump, it sounds like someone smacks the back, right side with a hammer. It only makes this noise when going over bumps. I thought maybe I had a loose wrench or something that dropped down into the wheel well in my trunk but there's nothing there after a thorough search. When I had my CV joint replaced, the mechanic took it for a ride. He noticed the noise and said my leaf springs are bad. Does that sound right? Anything else it could be? Thanks for any info!