Loud clunk sound when braking

[hospitalbuilder]

99Q has a loud clunk sound when braking. Started off that the sound only occurred when I was changing direction (i.e. if I was driving forward it happened once, and then would occur again once when I went in reverse). Best I can tell the sound is coming from the front when the brakes are applied. Since it was mainly occurring when changing direction, I figured the pads were loose in the calipers and would slip forward or backwards when the brakes were applied just after switching directions. But now it is occurring almost every time I have to apply the brakes with any pressure. I pulled the pads and reinstalled them last weekend. The sound went a way for a day or two, but then came back and sounds worse (could just be me turning the radio down to listen now though). Fortunately, I am not noticing any loss of braking power. Plenty of life left in the pads, so I don't really want to do a replacement right now.

Any thoughts on what might be causing this? Thanks for your help.