If your's is what I had a problem with, you can buy the bearing kit, and it's just going to do the same thing. In my case when the idler arm was not maintained for a very long time the bushing inside went mushy. That allowed movement, almost like a jack hammer inside its k frame mount. I just removed the idler, Tack welded 2 thick washer to the frame. ( you'll be able to see were it started, and where it migrated to.) Than I replaced the idler, and the grade a bolt. It no longer used the bolt with the crown nut when I did it. I think I used the next metric size up it was almost identical looking, but had machine thread, with a nylock nut. That fixed it for good. Make certain to install the grease fitting, and maintain it.