3 point hydraulics 1980 Ford 4110 3 cyl gas tractor

[slim357]

Ok, well, I am rebuilding a tractor I bought from an elderly guy who started taking it apart. I am working on the 3 point linkage system and I have used most of the parts in the box except for a few bolts. It looks like in the picture something is supposed to go into this plunger but not sure what? This looks like the only thing I am missing as of now. I think it is a turnbuckle assembly. Any thoughts would help and if I need parts where is a good place to get them? This is my 2nd tractor I have ever owned, my first was a hand crank B Allis. Thanks.
Doug