Need help with another clunk - rear axle - mostly while braking

This clunk has developed over the past couple weeks. It happens almost entirely while braking over a bumpy surface. If it get's really bumpy it will clunk without needing to brake.

Cycling the suspension won't create it. Only over small bumps.

https://www.youtube.com/watch?v=PO8SWHp9fiU

1st clip - these just the brake pad/shoes reseating. Unrelated but annoying

2nd clip - probably the best example. You can see how the axle twists and pops up, creating the sound

3rd clip - more clunks while braking

4th clip - braking on smooth road. No clunks. Also some good axle wrap.

5th clip - more clunks while braking over bumps​

Something to do with the drums??

The clunk is definitely noticeable in the video, but as always it doesn't quite capture how loud it is irl.

My brakes have been starting to squeak lately too, and those loose brake clips have been getting annoying, so I'm dropping it off at the shop tomorrow to fix and have them take a look. I'm hoping this clunk is related.

Thanks for any input.

 

Have you checked the torque on the bolts for the springs and shocks? Any signs that the bolt from the leaf spring clamp is making contact with the fuel tank?