Contact Galion; they might be able to furnish you an hydraulic schematic, or at least a manual.
I had a Galion 102 with an IH UD14 engine. Used it about 3 months cleaning drainage ditches then sold it again for a profit because I needed the money.
Really like the hydraulics on that grader. I set the blade at an angle, put the leading end down against large rocks and raised the blade and it would roll those rocks right up on top of the ground so we could drag them off the field. Worked better than a bulldozer for that job.