If it were my car, I'd first double-check the parts Dave suggested. The passenger side ball joint would be "numero uno" on my list. Then make sure the "new" rack isn't defective. A bad ball joint or defective rack are serious safety concerns. The "clunk" could also be the passenger side strut mount or, less likely, the large control arm bushing. Put a large wrench on the top strut nut then try to turn the nut. If it turns the strut mount or spring seat are shot. Look inside the strut for damaged parts. Try to slip a pry bar by the housing and push on the large bushing to check for movement. See if you can peek in there and look for damage or wear.

Post back with your findings. Good luck!