Which suspension part to change?

Have some clunking when I brake... new rotors new pads so must be suspension related?

Made me think of a more general question: how to tell when for example it's a bad ball joint vs outer tie rod vs lower control arm etc?? Is there a good process to eliminate?

 

Pressing brake pedal also says you take foot off gas and Engine braking starts. So twisting of drive/propeller shaft reverses. Have you tested for clunk when stopped? Shift from "D" to "R" and listen for clunk. Then shft "R" to "D" and listen for clunk.
If you get a CLUNK it suggests U-joint problem!

 

Thank you it's not lower control arm bushings!

I just started examining all the components and was curious how folks determine what requires updating/replacing

 

Try the R to D and D to R test as mentioned previously but repeat the test with the rear diff locked and report back with your findings.