Thanks for the info. I inspected the bushing and the bolt and could not see any obvious wear on either one. The only thing I could find was that the bracket had side to side play even with the nut torqued down as tight as I could get it. The bushing stuck out just enough to allow the for the side to side play. Now the idler does not bounce around and the spring does not vibrate. I just hope that I do not have things too tight and cause something else to break. Time will tell I guess, if the spring does start hitting the pulley again I am going to try the suggestion to use the half spring and move the mounting plate. Even now with the spring not bouncing there is not a whole lot of room between the spring and the hydro pulley bolts, bad design all around. Pete