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Tight hydraulic fittings

Discussion in 'General Industry Questions' started by Welder Dave, Jun 25, 2022.

  1. Welder Dave

    Welder Dave Senior Member

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    Can hyd. hose fittings become super tight over time? I had to remove the 6 hoses from my backhoe valve that go down the boom and they all needed a snipe to get loose. One almost didn't come loose and started to distort the nut. I've had the hoses off before and put them on snug using the proper size wrench but certainly didn't reef them as tight as possible. What would cause them to be so tight to remove?
     
  2. funwithfuel

    funwithfuel Senior Member

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    BSPP and German metric will both flare the tip of the fitting if over torqued. JIC and ORFS usually won't get messed up except for rust.
     
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  3. willie59

    willie59 Administrator

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    If the fitting is out in the open a hammer is your best friend, and I $hit you not. Any fitting, smart whacks of the flats of the fitting nuts, the more flats you can access the better. I'm not talking about beating the hell out of it, just smart whacks on the flats. Does two things, 1) slightly expands the metal of the nut from compressive hammer blows, and 2) disturbs the thread connections, sort of like the difference between a wrench on a nut opposed to an impact gun. Some smart whacks on a fitting nut and I promise you it will come loose with ease.
     
  4. Welder Dave

    Welder Dave Senior Member

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    Really hard to smack on a backhoe valve with multiple connections in close quarters and upper and lower fittings. Had to remove the top hoses to be able to get a wrench on the bottom ones. I got them loose but boy they were tight. Never heard of using anti-sieze on JIC hyd. fittings but maybe just a touch would be a good idea?
     
  5. JLarson

    JLarson Senior Member

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    Air hammer and a long punch or chisel.
     
  6. Welder Dave

    Welder Dave Senior Member

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    Sounds like like others have had the same problem.
     
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  7. willie59

    willie59 Administrator

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    Hammer and a long punch or chisel. I've done it on tight quarter fittings on valve bodies. I'm telling you it works.
     
  8. Welder Dave

    Welder Dave Senior Member

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    I'll have to try that next time.
     
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  9. 1693TA

    1693TA Senior Member

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    I have warmed them no hotter than you would do with a propane torch and they have come loose. A second person running an air hammer while you turn a wrench works well also.
     
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  10. Welder Dave

    Welder Dave Senior Member

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    I considered warming them up with a hand held propane torch.
     
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  11. 1693TA

    1693TA Senior Member

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    The drawback to using propane is it is slow to warm the metal so both the female, and male threads tend to expand together gaining little. Acetylene, or another fuel gas heats quicker expanding the female threads faster than the male threads making loosening the fitting easier.

    I am assuming you have female threads on your hose ends.
     
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  12. Cmark

    Cmark Senior Member

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    Excluding rust, one thing. Overtightening. There's only one thing that boils my p!ss more than a hose fitting that has been reefed on so much that the nipple comes loose when you try to undo it. The recommended torque for a 1/2" JIC fitting is only 40 lb ft. Go easy people.
     
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  13. terex herder

    terex herder Senior Member

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    I agree with the proper torque comment, but some of the china adapters have to have the hose tightened way past proper to get the drips to stop.
     
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  14. 1693TA

    1693TA Senior Member

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    And fittings that have been reused a time or two tend to leak if not overtightened......
     
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  15. shopguy

    shopguy Senior Member

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    if you Use a open end wrench make sure that it fits the flats really tight or it will ride up the humps and squeeze the nut,I found this out the hard way trying to get by with I had with me at the moment
     
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  16. Welder Dave

    Welder Dave Senior Member

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    I probably had them a little tighter than 40 ft./lbs. but certainly didn't use a snipe on the wrench like I had to to get them loose. I'll make sure to put them just snug when I put them back on. I also think fittings that have been reused need to be a little tighter to stop any leaks.
     
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  17. funwithfuel

    funwithfuel Senior Member

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    I wouldn't go light on reassembly, not with JIC. The flares and tapered seat are designed to be "tightened up " As soon as you put it to work and get a little vibration, you'll have a leak.
     
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  18. Welder Dave

    Welder Dave Senior Member

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    I'm wondering if there is something that could cause the fittings to become tighter, whether it's temperature changes or just over time they become tighter.
     
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  19. funwithfuel

    funwithfuel Senior Member

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    Like i mentioned earlier, a little corrosion can make things difficult. Aside from that, if the last guy pulled crazy torque and deformed the threads a bit, that'll make things rough.
    Now someone mentioned striking the flat with a hammer and punch. I've done that, it has both helped and hurt. I buy the right wrenches cuz, well, I'm a dealer tech and people tend to frown on seeing gouges and dings.
     
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  20. mekanik

    mekanik Senior Member

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