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Hydraulic pump problem

Forum Forums Tractor Troubleshooting Hydraulic pump problem

This topic contains 7 replies, has 4 voices, and was last updated by  mag 1 month, 1 week ago.

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  • #47073

    mag
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    Hydraulic oil going into engine.  I have no quick disconnects and  plv22tstkab Brand Hydraulic FEL valve. I  rebuilt the pump and seemed to work fine for a few hours and then lost hydraulic pressure and hydraulic oil going into engine again.  Just a bad pump or could something else be causing the problem?

  • #47074

    DavidPrivett
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    a pressure gauge should tell you , could your system be dead heading and causing it to blow out something the system? what did you find wrong with it when you had trouble before?

  • #47075

    mag
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    Forgot to mention it’s a jinma 284.  I didn’t find a problem last time just rebuilt the pump.  No quick disconnect connectors so what would cause dead head

  • #47076

    DavidPrivett
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    the valve control body there was a guy who just found a loose screw in a joystick valve ,his problem was a slow movement but the idea of the problem is the same a restriction of flow  . search on this site you should be able to find it.

  • #47077
    Tinbender
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    I’m no hydraulic mechanic by any means but the only logical answer I can think of is a blown rear seal on the pump. How else could the fluid get into the engine?  If it were me I would take the pump back apart, check for runout at the rear of the shaft (maybe a bad bushing or bearing) and look for wear on the shaft where the seal sits. If everything checks out put a new seal in and reinstall it and put a gauge inline to look for a dead head situation. Check it immediately after starting the engine. I’d like to hear from Bob Rooks or someone else who actually knows their way around hydraulic systems but that’s where I would start.

  • #47078

    mag
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    A new pump will arrive soon and I am installing a external relief valve at the out put of the pump set a little higher than FEL relief. I am also installing a gauge to keep an eye on pressure.  So I shouldn’t blow the pump anymore.

  • #47079
    Bob Rooks
    Bob Rooks
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    Sounds like there is something that’s keeping the relief valve from functioning, or it is set too high, assuming the pump is in proper working order. Yes, a blown seal is the only way hydraulic oil gets into the engine. A pressure gauge will tell the story.

    Have you ever cleaned the valve? How is your return filter?

    Yuchai dozer, Mustang skid steer, Mitsubishi mini-ex, Dual Dozer w/twin laser receivers, '50 Ford COE transit mixer.

  • #47080

    mag
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    New pump, new filter, added gauge and external relief valve. At present both the external relief valve and the FEL valve are set at 2ooo psi.  Anyone see a problem with them both relief valves set at the same psi ?

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