Anything from a tap to a knock when going over bumps, even small ones. Not dependant on steering wheel position. If the car is jacked up, you can feel play in the ends of the links. Pull in and out and up and down, any clicking and you've found the problem, or one of them. In your car we see a couple of things causing that same type of noise going over bumps. Sway bar links take first place, they're under a lot of strain because the sway bar in these cars plays a big role in stability. Tied for second are Struts and Balljoints. Struts and upper strut mounts go bad occaisonally. Pop the hood and kneel on the bumper, watch and feel the top of the strut as you bounce that corner. If there's a lot more up and down movement on one side, that's the disease. Ball joints are trickier to diagnose ithout being able to lift the car up and pull on the control arm. Most shops/ dealer's don't charge anything to diagnose a suspension problem, because they want you to have them do the work. Best of luck.
Keep those steering stops greased,
Chris
Shop Manager, Mitchell Volvo Service