I have a "thunking" noise on the passenger side rear of my 99 XK8. I looked for everything that could be causing it, but find nothing. I keep thinking it is in a suspension component....any ideas?

 

check out your shock bushings. Probably worn out. You can replace just the bushings (press out and in) or replace the shocks. Let mileage be your guide.

 

Thank You!

 

I've deleted you other identical thread from X150 forum. As you've discovered, this is the correct place to post technical questions about your model.

There's several possible sources on the rear suspension. In addition to shock bushings, the 'A' Frame bushes are a regular fail:


(click on the image to enlarge it)

As a general rule, where I find a bush/bearing failing on one side, I replace both sides as preventative maintenance.

Graham