2004 XC90 Popping sound from Driver side front

[xyourobob]

I am getting a popping sound from the drivers side front whenever I go over a pot hole or when I apply a hard brake. My first thought was the bearing on the top of the strut, since I was not sure and did not want to throw good money away I took it to the local independent mechanic. The indy said all my motor mounts were shot and the noise I hear is the engine on the frame, total cost $2400. I never changed them and the car has 205K on it so i said do it. This eliminated some minor vibrations I had in the car but I still had the noise. I was on the road for business and got snowed in so I took advantage of the time and took the car to another local indy and gave him the run down. They did some tests and said the ball joint is shot, total cost $245. I said do it for peace of mind, when he called me to pick up the car he said it did not solve the noise problem but assured me the ball joint was shot and even showed me a shot ball joint. he took $25 off the bill. What is causing this noise?