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Park Brake- John Deere 444H

Discussion in 'Wheel Loaders' started by jeradcdn, Aug 28, 2020.

  1. jeradcdn

    jeradcdn Active Member

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    Been having an issue with the E-brake on this unit, when the its cold the park brake works as it should, when its hot the park brake doesn't disengage. I have replaced the rocker switch in the cab, replaced the pressure switch and the solenoid valve.
    any thoughts on to where i should go from here?
    am thinking on replacing the park brake assembly?
     
  2. jeradcdn

    jeradcdn Active Member

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    figured it out, replaced the service brake pressure switch.
     
  3. mg2361

    mg2361 Senior Member

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    Well that was easy!:D
     
  4. jeradcdn

    jeradcdn Active Member

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    Same issue is back again park brake does not want to release when unit is hot, stop flashes on the dash buzzers sounds, have replaced solenoid and the pressure switch on the manifold. sometimes when you rev the engine up it will release, or let it sit turned off for 15 to 30 minutes and it will work .
     
  5. mg2361

    mg2361 Senior Member

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    Serial Number?

    When the issue happens can you read engine rpm? No rpm signal, no park brake release.
     
    BigWrench55 likes this.
  6. jeradcdn

    jeradcdn Active Member

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    as soon as someone comes and tries the unit again, i will advise thanks
     
  7. jeradcdn

    jeradcdn Active Member

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    serial number DW444HX564060
    tach is showing rpm, it seems like if they hit the hydraulic disconnect switch and turn it back on and then push the park brake switch then touch the throttle it will disengage. i have replaced all the filters thinking one may be restricting but not the case.
     
  8. mg2361

    mg2361 Senior Member

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    Check your charging voltage and post. Monitor it when the issue happens. Looking to see if it is overcharging.
     
    DB2 likes this.
  9. jeradcdn

    jeradcdn Active Member

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    its running steady at 27.9 volts
     
  10. mg2361

    mg2361 Senior Member

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    Sorry I have to ask, transmission oil level good?

    Did you check park brake pressure when issue is active?

    When the park brake applies you said buzzer is on and the red stop flashes, does the park brake indicator light come back on? Any other lights lighting up?

    Do you know how to access service codes in the monitor?
     
    Vetech63 likes this.
  11. jeradcdn

    jeradcdn Active Member

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    i haven't checked brake pressure, when the stop light flashes the park brake light is on at the same time. no other lights appear when issue happens.
    as for the codes only one that is recent is code 0386 but that tripped about 40 hours ago.the next recent one is 1653 and that tripped 500 hours ago.
     
  12. jeradcdn

    jeradcdn Active Member

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    ok finally had a chance to get back to this loader
    hooked up gauge to the supply line coming off trans to ebrake block, cold pressure around 200 psi, after running it for about half and hour the issue starts acting up pressure now at 150psi mark, fluctuates a little when i press the switch to release the brake but it does not release, light stays on dash, noticed that when pressing the switch a slight flicker of brake pressure light but it does not stay on.
    thanks for any input on this.
     
  13. mg2361

    mg2361 Senior Member

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    If that is the pressure you have going into the park brake solenoid block you need to check transmission system pressure. Park brake pressure spec is 218-260 psi.
     
    Vetech63 likes this.
  14. jeradcdn

    jeradcdn Active Member

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    at operating temp the pressure, read off the front of the transmission is 190 psi when put into gear.
     
  15. mg2361

    mg2361 Senior Member

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    At idle? The pressure test should be checked with the oil at 80 deg C, transmission in neutral and the engine speed at 1500 rpm. What do you have then? Spec is 218-260 psi (15-18 bar).
     
    Vetech63 likes this.
  16. jeradcdn

    jeradcdn Active Member

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    this morning, pressure at 1500rpm is 210-215 psi in neutral, at idle it's sitting at 140-150 psi in neutral, trans temp was at temp
     
  17. mg2361

    mg2361 Senior Member

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    Pressure at idle should be a little lower than system pressure but not that much lower. You have excessive leakage somewhere. You did change the transmission filter correct? If not do so and retest. If so then remove the line from the transmission filter that comes out the side of the filter head (not the lines that go to and from the front of the transmission next to the trans control valve) and goes to the cooler line near the torque converter and cap the fitting on the filter head and plug the line (use steel caps and plugs). Start your machine and see if transmission pressure comes up.
     
  18. jeradcdn

    jeradcdn Active Member

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    ok, the filter is new changed it a week ago, removed the line as described and capped ends, rpm @ 1500 pressure reads between 210-220 psi fluctuating at idle its 150-160 psi, the brake pressure light flashes off and on once in awhile as well
     
  19. Deere 444H texas

    Deere 444H texas New Member

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    Did you ever resolve this issue? Dealing with the same problem.