Hi,
I've got a bone-stock 2003 G35, 112k miles. I replaced upper and lower control arms as well as that thick 3rd arm (not sure what it is called).
Since doing so, I get a clunk when I hit the brakes. Didn't happen right away; drove it a little, then the noise.

It sounds like, when I hit the brakes, the caliper grabs the rotor and caliper rotates with the rotor until something solid stops it. But the caliper is solid. Not moving at all.

Anyone have an idea what this could be?

 

Could be a lot of things. I hate problems that involve clunking noises lol.

Do u have a worn bushing somewhere maybe?

 

2 most likely causes of clunks based on my own G ownership are lower ball joints and sway bar end links. If the problem is reproducible by stabbing the brakes at low speed in the driveway, you can put your phone under the suspension and video up and try to catch what's moving. Obviously be careful to line the car up and don't steer over your phone. Like this video of my Murano clunk. Suspension view is around 0:15 mark.