A sway bar helps limit the body roll or lean a vehicle experiences while it corners. The sway bar, also called an anti-roll bar, is a piece of metal bolted to the suspension on each side of the car. The link where these bars are connected to the suspension can become damaged, and the vehicle's performance will suffer as a result.
If the sway bar is broken or damaged, the link will break between the bar and the chassis. This will create some noise or rattling as you make turns. The bar will be hitting against the chassis and creating the rattle. This same noise might be heard when travelling over bumps as well.
If the sway bar breaks or becomes damaged, it can cause the vehicle to handle poorly. If the sway bar is broken, the car will lean more when making turns. If it is damaged but not completely broken, the car will feel loose when you make turns. It will lean but not as severely as when the sway bar is broken.
If you suspect something may be wrong with the sway bar, you will want to visually inspect the car. If the link is broken, you will be able to tell because it will not be attached to the chassis. Each end of the link has a series of bushings, washers and nuts. If they appear damaged, they will need to be replaced. As long as the sway bar is intact, then only its parts need to be replaced.