hello i have a duncan freehand zero but [you know the sidecaps] one of them is tight [you can not turn it with your hand] and one of them is loose [you can turn it] and it makes a really anoing noise so can you please tell me how to fix it 
I think the only way to fix it would be to remove it. Is the cap damaged at all?
no the cap is not damaged
i have a FHZ like that also. Before both caps were a little loose and make the click click click click noise. I actually kind of liked it. Then I traded one cap out and now it makes an annoyingscraping sound. I suggest taking out the stuck cap and barely sanding the edges a tap just so that both caps are the same - loose. You might enjoy the clicking sound, it’s kind of similar to the pod racing engines from star wars episode one. If not, try to take off the loose cap and place a small amount of silicone around the edge and wipe it and let it dry before putting the cap back on, it will tighten the cap so it doesn’t slip.
It seems that he is not a fan of such a noise, DanCDow.
I dont like the sound when one cap is losse and the other tight either. The sound i thought he might like was the two loose caps sound. click click click click click click click click click maybe i should have been more clear. good call.