I did find the rubber you mentioned. It is good. I paid a visit to our only truck spring shop this morning and was pleasantly surprised that the person I spoke with had a clue. If you are following this post you will know what I mean. He figures that as I am not carrying a load I could get by with having the buttons installed at the end of each leaf. He did not see the truck but I gave him a good idea of the wear. When I mentioned the elusive clunk/thump the first thing he said was spring bolts/bushings. So maybe we have found something here.
