Case 580K hydraulic cooler and supply lines, help needed

My machine: 1987 Case 580K Phase I (shifter goes through floor)

So I have a leak coming from one of the fat hoses that goes to one of the coolers ahead of the radiator- it's clean hydraulic fluid that's leaking. I'm trying to understand the hydraulic circuits and supply/return line "system". Some questions:

1. There are three cooling units in the radiator, from front (loader side) to back (engine side) they are: cooler 1 (very fat hoses, one on each side), cooler 2: smaller lines, engine...

Case 580K hydraulic cooler and supply lines, help needed

Case 580K hydraulic cooler and supply lines, help needed