OK folks. Here's the machinery. I see that a 513 has a few adjustments on the back braces that would affect the top link pickup point, but it looks like a direct hookup. One thing to invest in if its not there is a jackscrew type of link arm for the tractor. When the tractor and mower are not on the same plane, one side pin can be higher than the other. The jack screw link allows you to crank a link up/down as necessary once you get one side in. The other obvious hint is the Easy-Change connectors. You back in pick up the arms and they hook in. Note that the required lateral position of your link eyes is most likely gonna need to be readjusted. Set them for the lateral distance of the mower attachment pins. Normally I think most people set the height, get 1 pin in, pull the tailwheel over to get the 2nd pin close, push the link over the pin, hook up the drive shaft, and then connect the top link. Looks like the top link position is a floater. This means that the mower will hinge in the side view to adjust for ground elevation changes. The only other thing that comes to mind is that you rear wheels are set very close together and there is some interference now that was not there with the 4 footer. What is the distance between the rear wheel centers?
Other than that, we're gonna need a more detailed explanation of the situation you are struggling with. Lower pin(s) or upper? And what is the position of the mower F/A links on the mower deck? fwd or rearwd?
