Just in case you're still having trouble, some juices are known to swell the o-ring. It seems to help if you rinse it thoroughly in HOT water, and let it air dry. It *should* return to it's original shape. If all else fails, you can
buy baggies full of them all over the 'net (I can't seem to find the size on the bag of 20 I bought, and can't find it on here either, but one of the REO ninjas will be along eventually to post it, since they have all the specs memorized

)