Recently I've noticed some brake "metal on metal" noise randomly appearing when driving over bumps/dips and goes away randomly whenever it pleases.
When the noise is there as I approach a red light, the squeal gets quieter.
It sounds like it's coming from the rear pads.
I've looked at all 4 pads and they got heaps of life on them.
I only just changed all 4 pads dec 2016.
Something loose perhaps?

If it's any help, I don't drive like I'm 20yo anymore. I brake sensibly thank you very much lol

Any advice welcomed