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Jacobsen HR-5111 Hydraulic Problem

Discussion in 'Mechanic and Repair' started by inspiron23, Sep 17, 2006.

  1. inspiron23

    inspiron23 LawnSite Member
    Posts: 5

    Hi, I have a Jacobsen HR-5111 11' mower with Kubota 51HP diesel. Unit works perfect, runs at a steady 170-185 degrees even on warm day. But I'm getting a problem with the hydraulics on the unit. When you run the unit for about 10 minutes...the low hydraulic charge light comes on, and it stays on till the unit is cool again. There is no abnormal sound coming from the pump, no diffrence in power, decks or drving the unit. I don't know what they problem would be, but I have a question here. Could this be a bad sensor, because if there really WAS low hydraulic pressure the low filter pressure lights would both come on too? Thats just question, I'm just asking for the possibility of a bad sensor. Anyone had this problem before?
  2. khouse

    khouse LawnSite Bronze Member
    Posts: 1,465

    to me that would be the cheapest thing to replace if you don't have the warm running specs and a pressure guage. Could also be that your fluid is old and breaking down loosing viscosity.
  3. inspiron23

    inspiron23 LawnSite Member
    Posts: 5

    Well, I actually haven't tried to change the fluid, since I don't know what should be in there in first place...and the manual doesn't say which kind, it only have a part number for pail/55gal drum. Would anyone know what to put in machine like that? I could probably call a Jacobsen dealer tomorrow and see if he would know.
  4. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,023

    That was my first thought, Fluid and filter change but I don't know squat about this unit so didn't reply earlier.
  5. inspiron23

    inspiron23 LawnSite Member
    Posts: 5

    Well that was my first thought too, but it didn't make sense for the Main hydraulic CHARGE light to come on. Owners manual states if that light comes on, there is usually a blown hose, broken fitting...ect.ect. Reading that it just didn't make sense to me for that light to come on only when the oil in the unit is hot. But today is a rainy day, I'll change the oil and filters and see if it still comes on. Thanks For your help.
  6. tj86430

    tj86430 LawnSite Member
    Posts: 2

    I'm having the exact same problem. What was the solution in this case?
  7. jay_mc1

    jay_mc1 LawnSite Member
    Posts: 152

    I know this is an older thread, curious if you figured out your problem? I have owned 4 different 5111's and have never had this problem. If there is no physical evidence of a leak then I think I would start with the sensor. I would also change the filter and hydraulic oil. Jacobsen will recommend a fluid through them that is somewhat organic so that if does spill that I will not kill the turf. I personally would changed mine every other year depending on hours I put on the machines, and would use a universal trans/hydraulic oil in them. If I remember right, the manual says about 20 gallons. You will use closer to 17 gallons because you can't get all the old out without draining every single hose.
  8. tj86430

    tj86430 LawnSite Member
    Posts: 2

    In my case I removed the sensor and attached an pressure meter in its place and measured the actual pressure while the light was on. The pressure was about 20bar, which according to the local importer's technical specialist is normal (he couldn't give exact figures, but he said that the threshold for the warning light is probably less than 10bar. His advice was to get a cheap adjustable pressure sensor and connect that to the light (the original sensor goes for more than 700EUR = $900 if purchased from local representative). Haven't done it yet, though.

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