Hydraulic Education

[wayupnth]

To all:

I am relatively new to tractors and am still learning. I recently bought a used post driver (King Hitter) to go with my JD 4520. The previous owners had set up the fluid return to go back into a power beyond circuit, not a dump back into the fill reservoir. This ultimately caused the fluid to heat and o rings to fail. I've fixed most of the problems but I think my lack of understanding of how tractor hydraulics are set up is hampering me. Every time I think I have it correct, I realize that really don't understand how the fluid flows. I have a power beyond as well as a second set of fittings routed from the rear of the tractor to the FEL to run a grapple bucket. Is there any publication or website that can help me understand how tractor hydraulics work and are set up, generally and for JD tractors? Questions like: what is an SCV and how is it set up? What is the difference between closed and open center valves, etc?

Gary

 

[Mike058]

I've learned a lot right here. Run a search with any term you're not sure about and more than likely you'll see many threads about it.

 

[kennyd]

Gary, use the search as suggested, everything you asked has been written about extensively here. Also, Here is a link to a Army Hydraulics Manual that is very useful.

To your specific questions:

SCV (Service Control Valve):
That is JD's name for a "rear remote", basically it's a valve that let's you control a hydraulic cylinder.

OC and CC systems:
Your tractor is a open center system, that means that hydraulic fluid is always moving through it.