Can anyone identify what kind of solenoids these are. I've come up empty trying to use Google. They're on a grader attachment.
Those are solenoid coils that should be available most anywhere hydraulic components are sold. I used to get them from Spencer Fluid Power. Remove the big nut and the coil will slide off the stud. Take the coil with you to match up. The square piece with the screw is just a harness connector. Loosen the screw and pull the block off the coil.
You can measure the inside diameter of the solenoid. It will be 22mm or 30mm. Grainier sell Aro brand. The 12v 30mm is part number 4KP76.