I'm getting a clunk sound in front when I hit the brakes while in reverse(ex.backing out of a parking spot). I've had this issue 20 years ago on a same model(210) and can't remember what it was. I thought it was the idler arm but it seems good. Any thoughts? I would think others have had a similar problem. I check the caliper bolts as well. It is fine while breaking going forward.

Check out your castor bushes, and obviously make sure
everything else is done up tight enough

It might just be your pads moving inside the caliper cradle. When you're moving forward, the pads are against the forward-most part of the cradle. When brakes are applied in reverse, the pads move in the direction of the rotor, making them to move about 1-3mm towards the opposite side of the cradle, thus causing a "clunk" when the pads make contact with the cradle.