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case 9030b hyd pump loads up

Discussion in 'Excavators' started by treecutter, Jun 7, 2019.

  1. treecutter

    treecutter Active Member

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    I have a problem with pump #2 loading up when i try to do a function that runs off #2 pump.
    i took the regulator that moves the pump swash plate off and the spools are free to move.the negative pressure is within limits. i have taken the regulator block off and took end plates off .i was wondering if something else could be making the pump load up. the front #1 pump works ok. when i move the machine the left track works ok but when i move the right track it would stall engine. trecutter
     
  2. Coy Lancaster

    Coy Lancaster Senior Member

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    There is an adjustment screw on the end of the regulator block loosen the big nut "1 7/16 wrench" and use 15/16 wrench to back adjustment screw out about half turn. See if that improves the function of the hyd.
    BTW did you change any O-rings while you had block off. There in an O-rings on this adjustment screw, these O-rings can go bad and allow oil to get behind piston and hinder it's operation.
     
  3. treecutter

    treecutter Active Member

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    I backed the adjusting screw out a good half a turn on pump #2 and it made no difference in the way it worked.I backed the adjusting screw out a half of a turn on pump #1 and it lost power but on #2 pump it makes no change.could it be something other than the regulator block causing the problem or could it be an o ring causing the problem. when i had the regulator block off i could move the pump swash plate by moving the bar that the regulator hooks to.treecutter
     
  4. treecutter

    treecutter Active Member

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    if when i back out the adjusting screw a half turn and it makes no difference does that mean the regulator is good or bad?. The regulator has two hoses attached to it ,does oil pressure on the negative hose cause the pump to be in low output or full load.you had mentioned an o ring on the adjusting screw might be bad. Would that cause the regulator not to work.Is there a way i can be sure it is the regulator that is the problem? I appricate all the feed back i have been getting. thanks.treecutter.
     
  5. Coy Lancaster

    Coy Lancaster Senior Member

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    Ok have you checked the fuel pressure at filter base? Which injection pump do you have on machine?
     
  6. treecutter

    treecutter Active Member

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    I checked fuel pressure .it has 7 pounds going to pump. it has a bosch ve injector pump.
     
  7. John C.

    John C. Senior Member

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    Does that machine have the Kawasaki pump on it?
     
  8. treecutter

    treecutter Active Member

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    My pump is a kawasaki. i will send a picture of my pump with regulator off.I can move the arm that moves the swash plate but not by hand.should i be able to move it with hand pressure?if i use a wrench i can move it .treecutter 136.jpg 131.jpg 136.jpg 131.jpg 136.jpg 131.jpg 136.jpg 131.jpg 136.jpg 131.jpg
     
  9. John C.

    John C. Senior Member

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    There are three things that I have run into on that pump that could cause what you are describing. The pump holds at low angle when the negative control pressure is high. That means when all the spools on the valve controlling that pump are in neutral the pump is at minimum flow. When you open a spool the pump has a limited load sense from the negative control but mostly goes to full stroke right away. The control valve in the pump senses main pressure from the pump and destrokes in relation to main pressure pushing a spool on one side and spring pressure plus main pressure pushing on the other side of that control spool in the pump. What happens is that the control spool and bore get worn and oil leaks by and upsets the balance and the pump stays on stroke over loading the engine whenever a function is operated. The other problem I've seen was that the swash plat cradle is sitting in half a cone bearing. The surfaces that contact the rollers develop notches and the swash plate gets stuck in the loaded position. The usual result is that the pump overloads the engine and you let off the joy stick and it continues to over load for several seconds and then lets loose. The last thing I've seen was the swash plate control piston and its bore gets worn and pressure oil bleeds by causing all kinds of pump output issues. The pump either over loads the engine when the load goes over a certain point and then you have to let off the joy stick to keep from killing the engine or the pump doesn't go on stroke at all. Things just barely move.
    T a gauge into the NC fitting to the pump and see that it drops pressure when you go to operate a function on that pump. If it drops pressure and the pump is overloading the engine, then you are looking at a tear down of the pump. Have you torn down the regulator to check the parts inside?
     
  10. TVA

    TVA Senior Member

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    Everything that John said plus check weather the feedback fork, the one that goes over the small pin you can see on that picture on the side ( touching the oil puddle ) is not broken, also the whole that part should be sitting on the servo piston fast and all the way to the shoulder of bigger diameter. Sometimes they get loose and walking off which ends up giving too much flow.
     
  11. TVA

    TVA Senior Member

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    Your lucky that 9030 have Kawasaki and not KYB!
     
  12. treecutter

    treecutter Active Member

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    thanks for the information. I will do the pressure checks. I havent taken all of the regulator apart.I have removed the plates and spring and the spools all look smooth and i can move them with my finger and they slide very smooth.I was thinking of changing the regulator from pump #1 with pump #2 and see what that would tell me. the pump #1 is working and the left track moves but when the functions that run off the pump #2 are activated it stalls the motor. would that tell me if it is the regulator or the pump? my other option to be sure if it was the regulator or the pump would be to take the regulator off a machine that is working and try it to see if it works.again thanks for the help,much appricated. treecutter
     
  13. John C.

    John C. Senior Member

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    The pressure check is where I would go first. I don't know if the front will go on the back but if so it would be good to know for all of us.
    Good Luck!
     
  14. treecutter

    treecutter Active Member

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    I took the regulator from the front pump and put it on the back pump and the back regulator on the front pump.it still works the same, the left track works ok but the right track still stalls the motor.so now i think the regulator is ok but i will check the negative control port and see what the pressure is. the manual says 350 to 500 psi. but i will have to get a hookup to do the pressure check.if the pressures are within limits then look at rear pump. I think i can take the rear pump off with out taking the front off but I could be wrong.the other hose on the regulator [flow control port] i'm not sure what the pressure should be or is it a case drain for the regulator? Thanks for responce i will do the pressure check and get back.treecutter
     
  15. TVA

    TVA Senior Member

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    Should have checked NFC pressure first, like John said!
     
  16. treecutter

    treecutter Active Member

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    the problem is i had the hyd tank drained and one regulator off. i would have had to put the regulator back on and filled with fluid in order to check the pressures. i had a mechanic check the pressure on pump #2 about a month ago and he said it was ok but he only checked one regulator. I want to check both and compare them.treecutter
     
    John C. likes this.