r taillight not grounding prooerly all the time

Ever since I've had the 69 Dodge I've had a problem with the right taillight assembly not properly grounding, even if the metal on the assembly and the metal clips that it screws into are clean. I have to remove the lens, shift the assembly back and forth against the clips until I find just the right spot, then carefully replace the lens and tighten the screws. It will then work for awhile, and eventually stop working again. I'm wondering if I should

A: replace the assembly, which I'm having trouble finding replacement parts for, or

B: attaching a electrical connector (the kind with a round hole in the center) and connect this wire from the taillight assembly down through the inside to another ground location. Since its a cargo van it doesn't have an interior panel that I have to remove to connect the other end of the wire to a better ground spot. Or

C: something else

Any suggestions?

I would just run a fresh wire from the lampholder to somewhere else that connects to the steel chassis.

i had my 108 rewired with the modern type fuse. it was a cost, but worth it. now i just jump in and go everything works.

Thanks for the suggestions. When I went to run a separate ground wire I discovered the issue was not what I thought. (the grounding of the bell housing to the clips) I assumed it was because when I shifted the housing it would work or not depending on the movement.

The problem was actually inside the socket and the shifting of the housing caused an improper contact. The hazard lights for example actually work without even being connected to the van via the clips, for example. After realizing this I unplugged the assembly from the inside, pulled out the contacts inside the socket, reinserted them, put the bulb back in, and everything now works like it's supposed to. Did a test drive on a bumpy road just to make sure it stayed working.