A sway bar, also referred to as an anti-roll bar, is a length of tubular metal that is bolted to both ends of the front suspension. Many cars also use a rear sway bar. When the car is driven around a corner, the sway bar acts a lever arm on the side of the car that is on the inside of the turn. This forces the suspension towards the ground, reducing body roll and improving grip and handling. A sway bar is a relatively simply device that is bolted to the car with brackets in the middle and drop links on either end.
Drive the car around corners at a quick rate of speed, but don't be reckless. Pay attention to how the steering and chassis respond to your inputs. If the car feels vague and darty, feels stable one second and then not stable a second later, the problem may be a broken drop link or worn bushings.
Listen for clunking noise from the front end. There are many things that can cause a vehicle's front end to make strange noises and clunks, one of which can be faulty sway bar components. If the sway bar drop link (the part that fastens the bar to the suspension) is broken or has worn or torn bushings, the bar may move around and make clunks when the vehicle is driven around corners or even over bumps.
Perform a visual inspection of the sway bar and the bar components. Loosen the lug for the front wheels. Jack up the vehicle with a floor jack and support it with jack stands. Remove the lug nuts and the wheels.
Inspect the sway bar drop links, which are the short parts that come off of the end of the bar at a right angle and bolt to the suspension. Make sure the links are not broken. Make sure that the bolts are tight and the bushings are in good shape and not torn or missing. Also inspect the brackets that hold the centre part of the bar to the chassis. There will be bushings under these brackets to isolate the bar from the chassis. Make sure these are in good shape as well.