Current Projects chat and miscellany

Thought I might have more luck with this question here - none in AQA

While on the subject of brakes, my front (bog standard caliper. Shimano exage I think) is "loose" on its spindle so that when you actuate it the whole thing moves forward slightly, giving a clunk and mimicking a loose headset when rocking the forks back and forth.

If you tighten it up though, the moving parts are too closely opposed to actually close and open. What bit do I need to grease? Or fettle? Or?