I have a 1988 lifted F150 with super swamper TSL radials. I notice a rattling noise from the front end. As I observe the truck moving at a slow speed (5 mph), I see one of the front springs vibrating. When driving the truck , the noise stops when braking. Ideas ?

 

Tighten up the spring mounting hardware. Or maybe a new spring. Pics or a video may be helpful,