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  1. #1
    Elite Member JasG's Avatar
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    Kubota L3240

    Default Deere 4020 hydraulic issue

    Just to make sure I'm not missing something. Our 1968 4020 seems to lose prime on the hydraulics after it has been sitting for a while. I don't see any major leaks and it's not losing oil. It started a couple years ago where after start up you would have to wait 10-15 seconds before any steering or you could do anything with the loader. Now it can take a full minute before any hydraulics will work.

    Does this mean the pump is on it's last legs or is there something more I could be missing?
    “Government is like a baby. An alimentary canal with a big appetite at one end and no sense of responsibility at the other."


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  2. #2
    Super Member Tx Jim's Avatar
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    JD 4255/Kubota M7040 HDC

    Default Re: Deere 4020 hydraulic issue

    There is a service bulletin to add a check valve to eliminate hyd oil drain back that causes this problem you mentioned.

  3. #3
    Super Star Member J_J's Avatar
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    Power-Trac 1445, KUBOTA B-9200HST

    Default Re: Deere 4020 hydraulic issue

    Why not check the pressure potential of the pump by using a hyd gage and see if the relief is set right and relieving at the set pressure.

    Check all your fittings and suction tube, you may have a suction leak.

    Have you looked in the tank for small bubbles.
    J.J.

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  4. #4
    Super Member Tx Jim's Avatar
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    Default Re: Deere 4020 hydraulic issue

    Here's a website pertaining to your tractors hyd problem I learned about several yrs back from another tractor forum. Fixing JD 4020 hydraulic loss

  5. #5
    Elite Member JasG's Avatar
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    Default Re: Deere 4020 hydraulic issue

    Quote Originally Posted by Tx Jim View Post
    Here's a website pertaining to your tractors hyd problem I learned about several yrs back from another tractor forum. Fixing JD 4020 hydraulic loss
    Thank you for the idea. I did see that last night while searching for this problem, only ours if fine with the clutch pushed it, it's just while sitting with the engine off. It's worth looking into though. It seems to have good pressure and I know he had a dealer mechanic pressure test it last year. He didn't ask about the prime at the time though because it wasn't that bad.
    “Government is like a baby. An alimentary canal with a big appetite at one end and no sense of responsibility at the other."


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