have they just lost the ball bearing that sits inside ? If they have, get 1 out an old freewheel, fit a treat . Josh. Acctually, not sure if they come with a ball bearing, might well of been a bodge , so try wackin a ball bearing in there, will give you a perfect seal aslong as its clean. Josh. Oh, and if this works, make sure to take a few out with you, 'because if you bleed your brake when your out nd about, your gauranteed to loose the lil thing .