If there is end play in the Draft Spring it needs adjusting. Look on the right side of the housing where the spring is and you will see a grub screw that needs a small Allen key to
slacken it, slacken it off a couple of turns and then lift the Rubber Cup on the end,you will see a large nut underneath with equally spaced slots around the inside,you need to turn this nut until the end play just stops and then lock the nut with the grub screw. only just tighten the grub screw,
if you over-tighten it, the threads on the nut will be damaged. There is a lead pellet underneath to prevent this damage so it never feels tight. If you over-tighten the big nut it can also cause free play as well, so try it both ways to adjust it.If you can't adjust the free-play then unscrew the large nut all the way out and pull the sensing unit out of the Tractor and clean it up and adjust any play that is in it before you replace it in the tractor again and then adjust it as I just told you. The bolt that you have instead of a Pin MUST be a good fit in both the Tractor and the Top Link or it will not sense the Draft properly and it won't be able to control unless it is a tight fit in both parts.
If you still have problems with all this, email me direct.John(UK)....firstname.lastname@example.org