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Hydraulic flow tester for cheap?

Discussion in 'Mini Skid Steers' started by Philosaw, Sep 1, 2014.

  1. Philosaw

    Philosaw Well-Known Member

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    I need to test the flow on my t190 and don't have a flow meter. In researching it I came across a used flow control valve for cheap and thought that maybe if I combined that with a gauge, I could get a reading on the health of my pump. Seems like if I hooked it up to the auxiliary hydraulic coupler I could start with a low flow and slowly increase while monitoring the pressure. Would this work as a poor man's flow meter?
     
    Last edited: Sep 1, 2014
  2. lumberjack

    lumberjack Senior Member

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    Flow meters measure flow and pressure, and you have the option to increase resistance/load. That valve and a pressure gauge only gives you the load and psi side of the equation.

    If it can make full pressure at idle (gear pump), that's a good start of a sign.

    I've thought about buying a flow meter for giggles.
     
  3. Philosaw

    Philosaw Well-Known Member

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    Well, if the hydraulics in my t190 have basically quit, then wouldn't the pressure at the required flow show me whether or not it's working? The flow valve is calibrated from .5gpm to 30 gpm. And yes, it is a gear pump.
     
  4. lumberjack

    lumberjack Senior Member

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    If the valve is set to 30gpm, but the pump is only putting out 5gpm, you would have no way to tell.

    A flow meter displays the flow actually passing through, and the pressure gauge reads the pressure. You can dial load in on most flow meters (adjustable flow controller/orifice/valve), or install them in a circuit to display the load occurring from the work being done.


    Again, if it can make pressure at idle with hot oil, it's not in bad shape.
     
  5. Philosaw

    Philosaw Well-Known Member

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    Thank you. That's a start anyway!
     
  6. lantraxco

    lantraxco Senior Member

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    When you say the hydraulics have quit, do you mean no drive power at all, or did you just lose the boom lift and bucket tilt?
     
  7. Philosaw

    Philosaw Well-Known Member

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    The hydrostatic pump is fine, but all of the auxiliary hydraulics stopped functioning out of the blue. I can't believe that it's the pump, but it seems like the first place to start. I've had gear pumps that never failed with all sorts of contamination over years and years, but the books says it's the most likely culprit. I'm definitely a bobcat novice!
     
  8. simonsrplant

    simonsrplant Senior Member

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    Two things... Flow meter on the cheap... Hmmm, good luck...
    And pressure is one thing completely different from flow. Do not be fooled by a pressure gauge, showing good pressure... If the volume, or flow is not there, things will not operate correctly. The only way to test is with a "proper" flow tester.
     
  9. lantraxco

    lantraxco Senior Member

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    You could theoretically use a pressure compensated flow control (divider) with a pressure gauge: A) if it has a built in relief valve, or B) if you tee say a 2,500 psi relief valve from the inlet to the outlet. Start with the flow control set to max flow, and with the engine at a reasonable speed, slowly decrease the flow until the pressure comes up to the relief valve setting. This would be roughly the flow from the pump as the valve will force any excess to flow through the relief.

    Mind you there may be some inherent danger of blocking a hydrualic line but the system relief SHOULD keep you from blowing anything up.
     
  10. crewchief888

    crewchief888 Senior Member

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    have you lost just the aux functions, or all hyd functions, ie: bucket and boom?
    you say the hydrostats work, so you still have drive on both sides?

    :beatsme

    :drinkup
     
  11. Philosaw

    Philosaw Well-Known Member

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    Thanks for responding. Yes, the drive works perfect. I just took it into Bobcat yesterday and paid $400 for a diagnosis (Yikes!). The mechanic said that the pressure at the pump was 1800psi and that the pedal switch was bad. Now, I get that, but...why then do all auxiliary hydraulics function the same right now? Seems like 1800 psi would allow for a fairly quick movement of all functions, but lack power, and the pedal switch would just cause the lift and dump functions to fail.
     
  12. crewchief888

    crewchief888 Senior Member

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    a pedal switch? :confused:

    do you mean the PWM paddle switch?

    T190 system relief pressure is approx 3200psi, unrestricted flow approx 20-22gpm...


    :drinkup
     
  13. Philosaw

    Philosaw Well-Known Member

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    He called it a peddle switch and showed me a solenoid to illustrate the part. He did have a heavy accent, so it's possible I misunderstood him. He also said a spool could be damaged and I asked if a screen could be plugged and he said that was possible too. As I pulled it into the shop I accelerated all the way and barely got the bucket all the way up. It shook as it rose, kinda like when the fluid is low.
     
  14. crewchief888

    crewchief888 Senior Member

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    sounds like you have a communication problem between you and the mechanic,

    as well as a possible hyd pump problem.....



    :drinkup
     
  15. bigsmoke

    bigsmoke Active Member

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    Perhaps your BICS valve took a dump, that'll have nothing to do with your hydraulic pressure though.
     
  16. Philosaw

    Philosaw Well-Known Member

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    I did replace the BICS valve, but it made no difference.
     
  17. Philosaw

    Philosaw Well-Known Member

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    I've been battling a major onslaught of broken shi** over the last few weeks and had to drop this project for a bit. So, I pulled the whole control valve because I don't believe that low pressure is the problem. I also don't believe that low flow would keep all hydraulics from functioning at all if there is 1800 psi at the pump. That said, I still don't know what would cause it and will go through the control valve stem to stern to eliminate that as the problem. While I have some mechanical skills from maintaining my own fleet of equipment for 40 years, I am a complete bocat and hydraulics rookie! I have a seal kit coming for the control valve and a new pump on the way as well. If those two things don't work out, then I will probably send it off a cliff or to the scrapyard:)
     
  18. melben

    melben Senior Member

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    It takes more than pressure to do work, if the pump pressure is suppose to be in the 3000+ range and is 1800 that is a bad sign for sure....If you have 3000psi but at 0 GPM you get NO work done. A flow test will tell you what you need to know. I would want to be there watching the test and I would want the pump hooked up directly out of circuit with the flo tester outlet back to tank. That test must be done carefully by a trained tech as if improperly done a split pump housing could result. Many , but not all would not know how to interpret a flo test if they had a tester, I was trained at Case's service school at Racine. The Case dealership that I worked at tested each Bh/ldr as part of the predelivery and its results logged in case of a failure of any sort in the future .

    I used a Tee test which allows every system tested from one hookup. Once a pump test eliminates the pump as a problem I would use that hookup
     
    Last edited: Nov 5, 2014
  19. Philosaw

    Philosaw Well-Known Member

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    Yeah, thanks. You are absolutely correct. I did end up reinstalling the valve and installing a new pump. The pump did the trick. I guess what got me was the inconsistency of the failure, it went out then returned then went out again. I learned a lot though and am no longer intimidated by the machine. I also bought an inexpensive guage and fitted it to an auxiliary port and the new pump tested at over 3000psi. Now that I know more, I'm baffled that the bobcat tech didn't do a flow test and basically guessed at what was wrong. Don't really appreciate guesses for that kind of money! I can do that:)
    Thanks for your info.
     
  20. Deeretracks

    Deeretracks Senior Member

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    Don't be too shocked. Good mechanics are in short supply and dealers usually pay less than private contractors. Dealer techs have access to lots of training and tools but it's up to them whether they use their skills. I know some pretty smart techs that do substandard work.