Case 580K hydraulic cooler and supply lines, help needed

[DualsportWA]

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 area, from front (loader side) to back (engine side) they are: cooler 1 (very fat hoses, one on each side), cooler 2: smaller lines, cooler 3: engine radiator. Can someone help explain what each of the two forward-most cooler elements are for?

2. Mystery: I have a fat hose that goes from the hydraulic filter housing to the front-most cooler element - that's the one that's leaking clean hydraulic fluid - has rubbed through (from rubbing against a steel tube next to it). I do not see this fat rubber hose on the diagrams for the hydraulic filter/cooler - can't figure out which part this is- any help would be appreciated! On the diagram (below) it shows this as a return to tank line, on my machine, this output from the filter head goes to the front-most cooling element...

Help!

 

[Theweldor]

Could be possible someone pulled a hose in when the steel tube leaked during its lifetime.

 

[DualsportWA]

I had that thought too- what's really a mystery is that it doesn't go back to the tank, but goes to the front-most cooler. Same basic filter housing, same output port - different hose and destination...

 

[DualsportWA]

Here's a pic of the hydraulic line going to the front-most cooler element (fitting is over 1" on the OD).

Behind the fitting, you can see the 2nd cooler element (middle) - still wondering what each element is for!

 

[Theweldor]

It has been years since I have worked on a K series machine. So I am of no help unfortunately. I do know that they cherish those steel lines immensely when you go to buy them, reason for the hose. There are a couple of people on here still knowledgeable on these machines. They will be along shortly I am sure.

 

[Tinkerer]

Here ya Dualsport. Right out of the service manual. Left click on the image and it will enlarge for you.

 

[DualsportWA]

Thanks- I just can't figure out why I have fat hoses going to a cooler that looks nothing like the parts I see listed online for a hydraulic oil cooler!

 

[Tinkerer]

Usually it is overkill by someone that replaced the originals. I have had hose makers try to sell me 4 and six braid hose when all I needed was a double braid. Just trying to increase their profits.