JD 2950 Hydraulic System

tjdub

Member
Can someone give me a quick run-down of how the hydraulic system flows on a JD 2950?

There are two lines attached to the side of the pump which appear to be high-pressure lines. There is also a rubber hose attached to the top of the pump that leads to a reservoir, cooler, then back to the transmission. Finally there is a plastic vent tube that connects the reservoir back to the pump.

Does oil flow from the transmission through the cooler on it's way to the pump, or is it the other way around?

I have a small leak somewhere around the pump, but it doesn't leak when running (sucking in air?) and it doesn't seem to leak immediately after I shut it off but after it sits for a while there's oil dripping out from somewhere. Also when I first start the tractor up the hydraulics are full of air so I have to run the loader up and down to cure the jitters, but then it works fine. I cleaned it all up the best I could last night so hopefully I can find where it's leaking tonight.
 
Maybe these 2 photos will help you find the leak. Line #17 is the pressure line from frt pump tp pressure control valve. Line # 9 attaches to oil cooler.
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Thanks Jim.

I'm still not sure which line goes between the transmission pump and the hydraulic pump though. Is it #9 or #10?

I see there's a ball in line #9 to act as a check-valve. So does that mean that that one is the return to the reservoir and #10 is is the hydraulic pump supply-line?
 

tjdub
The reason I didn't state which line supplied the frt pump was I was unsure and didn't want to make an incorrect statement. I think you're correct in that line #10 is the supply line to frt pump but I haven't looked in a utility tech manual since the late 80's.
 
For what it's worth, I figured out my leak. The plastic/vinyl "vent tube" that leads from the top of the reservoir back to the pump had a pinhole leak in it. Fortunately, it was long enough that I just trimmed it shorter with a razor knife and it had enough slack to reach back to the pump.

I still don't understand how the system works, but as long as it's not leaking, I guess I don't really care :)
 

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