my 2001 GS 430 makes a clunking sound from the right rear whenever I hit a bump in the road. If I touch the brakes lightly while going over the bump, then there is no clunk. I have replaced all the brake hardware,with no change.Does anybody have any ideas? Its driving me crazy.

Words are not better than physically seeing underneath. Highly recommend raising up the car on the hoist or jack and inspect it. GL.

might be a loose tophat bolt. check it if you installed any suspension lately.

Sounds like the rear shock mount which is a common problem on BMW's. I don't think Lexus has that problem, but it would be worth checking out.

Remove all your trunk lining around the rear shock towers and look around or maybe even have someone ride in trunk when going over a bump, maybe they'll be able to determine if the sound is indeed coming from there.

Good luck either way