John Deere 2720 - Zero Hydraulics, Zero 3-Point Hitch, Zero Answers...

[suburbanfarmer]

Well folks I finally found the problem! There is a seal inside the hydraulic pump (back side) which was blown.
It is the one which wraps around the two shaft ends (if that makes any sense) and prevents the hydraulic oil from diverting from the inlet/outlet portion of the pump.

Did you end up repairing it yourself or dealer?
Any chance you cataloged the repairs with pictures?

 

[MN2520]

I know this is an older post but I am having the exact same issue! I am going to pull apart my pump and look. JD doesn't show any break down or seals. Is there anything I should know before I start? Where did you get the seal?

 

[mark in portugal]

I had similar symptoms; in my case, it was a suction hose.
A steel pipe carries oil from the case/ reservoir to the filters, and then (on my tractor) there is a short section of large diameter rubber hose to the hydraulic pumps.
It's buried under things and difficult to see.
And a very cheap fix.

 

[MN2520]

I replaced the hose and the two O ring one at each end and it still happening....

 

[mark in portugal]

If the pump is turning, and there is oil at the suction side, then oil must come out of the pressure side unless the pump is broken.


Seals are available from bearing suppliers.

 

[Tx Jim]

I know this is an older post but I am having the exact same issue! I am going to pull apart my pump and look. JD doesn't show any break down or seals. Is there anything I should know before I start? Where did you get the seal?

Have you checked/cleaned hyd oil suction screen?

 

[MN2520]

Yes, I did a full hydro service. Cleaned out the screen and magnets, it was rather dirty.

 

[dieselscout80]

I don’t know anything about a JD 2720. That said with my IH tractor it can/will get air locked when I clean the suction screen.

I have to crack open the outlet of the hydraulic pump to get the air out with the tractor running.

Note the hydraulic oil will spray out, but the air lock is gone.

 

[mark in portugal]

I have a hard time getting the oil to flow after opening the suction side of the system for anything (even filter replacements).
I pressurize the case a little bit with compressed air with the engine running to push it through to the pump.
I have no idea what the "correct" method is.

 

[MN2520]

I pulled the pump, both the suction side and the high pressure side were empty. Including the whole pump. It looks like the input shaft seal is bad. I have no idea if this is part of my problem or not.