Absolutely replace it. I just replaced both of my front control arms about 2 months ago. The driver's side had rusted right through and was literally in two pieces - on the car. I didn't discover this though before I went on a long road trip. When braking the car would veer to the left. It was incredibly dangerous, and frankly, I'm lucky no one was injured. I found an excellent replacement pair - completely rust free - online. I probably could have replaced them myself, but I took them to my mechanic to install. He was shocked that I was able to drive the car at all. DON'T let yours get to this point, as a serious accident is inevitable! If that's all that's wrong with your 240, you'd be foolish to junk it.