clicking sound from left rear wheel

I have an 80 ZX 2+2, and the other day it started making a clicking, metal to metal sounding noise coming from the left rear wheel. It is sometimes intermittent, and only starts after I apply the brakes a good first time. And when I do apply brakes, the noise is subdued quite a bit, but can still faintly hear it. Anyone have any thoughts at all? Appreciate it.