front suspension popping noise

[BUICKGN805]

I been having some weired popping or cracking noise on the front suspention of my GN. Iv changed everything about 2 years ago or less= controll arm bushing upper/lower (polyure), all ball joints, end links, sway bar bushing,idler arm,center link,all tie rods,gearbox,bearings,Eibach springs,bilstein shocks and everything is greased. At times I hear squeeking is when i turn a corner at 5-10mph, and the popping/cracking noise happens when Im coming to a stop applying the breaks before a complete stop it pops from the passenger side then driver side? Iv check even the bolts everything is good and tight. I recently change UPPER controll arms for tubular ones. It made no differance. Any Clues...