Can you post up a photo or two? If they are running a rotary style bearing with balls or needles, then your issue will be either the bearing has collapsed or the shaft has corroded and reduced in diameter, OR if its a bronze or sinterd bush, it will be a push out job. The bush to tube fit is probably going to be tight as typically they would run a reamer thru the bush after it is inserted into the tube - well thats the way I would do it. You will be lucky to get an 'out of the box' solution if its a bush I would think, but with some monkey work you could get there with patience.