Since I purchased my used '98 S70 at 43,000 miles (now at 55,000), I have heard a hollow pinging or knocking noise when I come to a complete stop after driving a bit. On the drivers side and under the car on the floor. Any ideas? My dealer thinks I'm nuts.

Simple solution - take your dealer for a ride in your car and demonstrate the problem. Also give them written instructions for how to re-create the problem and test the fix once they are done. They will stop thinking you are nuts, and fix your car.

I have done that several times; hence them thinking I'm looney. They have even taken the car overnight. It always happens with me (and I have witnesses! My passengers hear it as well! Just not any Volvo mechanics) but they claim that they never hear it. Is there anything that has to do with the break that would "ping"? And it usually comes in cycles of three's. Yup, I know. ..crazy.

Does it feel like the noise is coming from behind the drivers seat, if so I get the same pinging noise & was told it is the abs!

I believe it's coming from the floorboard by my break. Why would the ABS "activate" to make a ping at a "normal" stop?