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Hydraulic Fluid Leak at Reservoir Fitting - Need Help and Suggestions


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I have a small hydraulic fluid leak on the return line of the the hydraulic system at the fitting of the reservoir.  It is leaking out where the brass 90 fitting and hose connection is.  See pic below.  I am not familiar with the yellow compression fitting, and so I am looking for help on how I can stop the leak.  I have tried a hose clamp, but that does not stop the leak completely.  

Should I just replace the yellow fitting?  What are they called?  How do I remove it?  This is new to me.

Thank you everyone in advance.

 

920158936_HydraulicFittingLeak.thumb.jpg.7b4a180711d4d79979cf4c53a2276e0a.jpg

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Looks like it's leaking where the hose slides on the fitting. Can't tell for sure but it looks like the fitting is a barbed on the hose end and swivle flare fitting on the other. Do all those type hoses have clamps on them? Most fittings like that don't require hose clamps.

Usually the hose is held on the fitting with barbs and the easiest fix is to cut back the hose 1-2" and push it back on the barbed fitting. Heating the hose in some hot water helps to get it all the way on.

I could be wrong on the type of fitting, mine has -4, 3000psi hydraulic hose and I've had to replace 4 failed crimps and need to do a fifth.

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7 minutes ago, Old Dog said:

Looks like it's leaking where the hose slides on the fitting

Yes that is where it is leaking.  I put the hose clamp on, trying to stop the leak.  It was not there originally.

After searching the internet I found a similar fitting with the yellow ring.  My yellow ring is cracked at the top.  Does that matter?.  So is that failed?   As suggested should I just cut some of the hose off and push back on the barb fitting?Push-on-N68017-90-MNPT-Barb.jpg.b9f27ad58a3797ae0e849411099b79f7.jpg

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I just looked at mine and it has the same hose and yellow ring.  I think cutting back the hose and pushing the undamaged hose might work, but you may have to drain the tank.  You might try moving the hose clamp closer to the yellow ring before cutting the hose.

good luck!

 

 

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I would check to see if the two fittings are compatible. 

The 90 degree coming out of the tank almost looks like a male JIC flare type compression fitting.

The straight one coming from the hose has to be female swivel type to properly seal. 

The only way to know for sure is to take the two apart so you'd have to drain the tank to check it.

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2 minutes ago, jacwjames said:

I would check to see if the two fittings are compatible.

Absolutely James.  I was just showing that pic as a reference to these type of fittings.  It seems that the yellow ring has no purpose other than a stop for the hose?

I am going to call a local hose and fitting supply shop tomorrow and ask if the yellow ring has any purpose for having a tight seal.  I am guessing no.

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Yeah, the ring has no sealing function. It is good to have with steel braided hoses to keep the wire ends contained. If you have Aquahot, you might have the same thing on the fuel line fittings too. It is for looking pretty.

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That kind of hose clamp on a barbed fitting will probably do more harm then good. If you us a clamp use the automotive style, they provide evenly distributed clamping force and can't be over tightened which leads to cutting the hose on the barbs.

You might check the condition of the hose, if it's hard and stiff you should replace.

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1 hour ago, jacwjames said:

Can  you tell if it's leaking at the two fittings?

Thank you all for commenting so far.  Your comments have caused me to begin to think that if this is a swivel barbed fitting, I am suspecting that the leak is coming from the swivel portion of the connection point and not the barb and hose connection point.  In fact that is where the hydraulic fluid collects, between the yellow ring and the brass ring part of the barbed connector.

If this is the case, that might explain why the hose clamp does not stop the leak.

What do you think if I tighten the barbed swivel connector a bit on the 90 fitting to see if that compresses enough to seal the leak.  If not, I will replace the barbed connector.  And like all of my former air line swivel connectors, I will replace it with a non-swivel connector.  I don't really see the reason to have a swivel connector, just another potential place to leak again in the future.

5 minutes ago, Old Dog said:

You might check the condition of the hose, if it's hard and stiff you should replace.

Thanks Don -  Hose is still in good condition.   If I determine the leak is on the barbed and hose connection, great point to use automotive clamp.

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If you look at the photo closely either that clamp or another one was closer to the end of the hose at one time. Either way that should be a very easy fix. Do you have a pvc/ rubber hose cutter? If you would choose to temporarily fix it with another clamp find a narrow one to be sure they are both on the barb and rotate it 180 from the other if possible.  

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I have to track down a small hydraulic leak on the driver's side engine compartment that developed on our trip up north to New Hampshire last month. It only leaks when the engine is running.

I thought the hydraulic system was under some pretty hefty pressures requiring compression fittings and not barbed and hose clamp fittings.

Is my understanding of the system wrong?

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2 hours ago, Dr4Film said:

I thought the hydraulic system was under some pretty hefty pressures requiring compression fittings and not barbed and hose clamp fittings.

Richard - you can feel through the hose the barbed profile of the fitting on the reservoir for mine.  I am not sure of the rest of the system, but for the reservoir it is barbed.  It is under some pressure.  My manual says the return line pressure is around 85-100 psi.  I read somewhere that barbed fittings are good to 150 psi.

The manual also says that after the hydraulic pump it can get up to 2000 psi.  So depending on where your leak is, the pressure will vary significantly and obviously require different types of fittings and clamps.  My leak is only when it is running also.  Good luck with finding and fixing your leak.

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Just a word of caution for anyone looking for a hydraulic leak on any lines that have high pressure.  

At work+30 years ago had an employee looking for a leak under the controls on a drill rig.  He started feeling around with his had and moved it across a pin hole hydraulic leak under high pressure.  The hydraulic oil was injected to his hand under the skin.  This was a very serious accident, the employee spent days in the hospital with multiple surgeries getting all the oil out from his hand and then months off work. 

So be careful when looking for leaks with anything under pressure. 

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  • 3 weeks later...

Update - replaced my leaking hydraulic barb fitting.  It was leaking at the swivel so had to replace with a new 3/4" 37 Degree JIC Female Swivel Hose Barb fitting.  Also put in a coupler to extend the fitting as I had to cut some of the hose and there was literally NO slack in the hose.

I had planned to go with a non-swivel fitting, but my local supply house did not carry those.  Anyway, if it doesn't leak for the next 16 years, I'll be happy.  Toughest part of the job was taking out the nearly 5 gallons of ATF and putting it back in.  Was made easier using my drill pump.  

image.thumb.jpeg.f90f33fe2794a0517ccdda764ceff100.jpeg

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