How to Get Hydraulic Coupler Off?

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SteveHGraham
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How to Get Hydraulic Coupler Off?

Post by SteveHGraham » Mon Apr 09, 2018 5:42 pm

I'm tired of oil dripping on my workshop floor, so I want to take a crack at putting a new hydraulic fitting on my tractor. See the photo.

It appears that fluid is dripping downward onto the male threads on the center fitting, down near the bottom. There is an angled fitting with hex sides on it at the very bottom. Then there are the male threads. Then there's a round nut with two flat spots. It's not a hex.

I think I need to turn the round nut clockwise to take the fitting off the threads, but there is no room to put a wrench on it. It looks like someone tried to put a pipe wrench on it a long time ago.

How am I supposed to take this thing off? I think I can get at it if I take off the fitting to the right, but then I open myself up to the danger of creating a new leak when I reinstall that fitting.

I don't know why a threaded connection would leak. I am concerned about the condition of the male thread as well as the coupler threads. I don't know of any way to test it except for doing the whole job and then using the hydraulics. That means I could end up doing this job over and over until the leak goes away.

I read about a sealant people put on hydraulic threads. Wondering if I should use it.
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04 09 18 hydraulic fittings on kubota crop.jpg
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John Evans
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Re: How to Get Hydraulic Coupler Off?

Post by John Evans » Mon Apr 09, 2018 7:05 pm

What is on the top of that center fitting ? A hose? If so that is a quick disconnect I believe. If so try sliding that knurled sleeve downward to release the top section. A "crow's foot " that has a square drive might get you enough movement to get the fitting body [coupler body] out. Most likely the sealing areas in side that body are worn causing the leak.
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SteveHGraham
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Re: How to Get Hydraulic Coupler Off?

Post by SteveHGraham » Mon Apr 09, 2018 7:22 pm

It's a quick coupler, as you say. I can get the hose off, but the coupler itself looks like bad news.

I was thinking about a crow's foot wrench, as you suggest. Not sure I can get it in there.

You may be right about the leak coming from inside the coupler. I only saw oil on the threads, though, so I am suspicious of them.
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warmstrong1955
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Re: How to Get Hydraulic Coupler Off?

Post by warmstrong1955 » Mon Apr 09, 2018 7:41 pm

The term 'quick'....is relative. :)

First off, clean off the muck & leaves.
In case you are unsure how to un-attach the quick coupler.....
Push down on the male coupler, before you try sliding the sleeve down to release it.
Wile pushing down, you should feel it move somewhat, then you can slide the knurled sleeve downward. You may have to wiggle the male end while doing it.

Next...NPT threads are the worst possible threads for all things hydraulic. No surprise it leaks. I hate 'em. They stink. Lots of people hate 'em. But they are still used a lot, especially on ag equipment.
NPT is why God created ORB, split flange, and ORS.

Remove the 45 degree hose end to get it out of your way, and probably the 90 degree adapter it attaches to, so you don't bugger up the JIC taper on the adapter. As long as you don't bang up that taper, all will be well when you put it back together. (When you reassemble, do not over-tighten it)
If there is no hex on the base of the female q-coupler, you can use channel locks or a pipe wrench to remove it. Even vise-grips.

Teflon pipe dope works best.
Clean the threads, and remove the oil. Put on the dope & tighten away. Cover the male threads WELL. Hard to over-torque pipe threads, just don't go totally nuts.

:) Bill
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warmstrong1955
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Re: How to Get Hydraulic Coupler Off?

Post by warmstrong1955 » Mon Apr 09, 2018 7:51 pm

I use this: https://www.amazon.com/Permatex-80632-T ... Bdope&th=1

Loctite makes some good stuff too.
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SteveHGraham
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Re: How to Get Hydraulic Coupler Off?

Post by SteveHGraham » Mon Apr 09, 2018 7:52 pm

Thanks. I assume I should go for a new coupler instead of hoping the old one works after reinstalling.

BTW, I cleaned off the crap AFTER taking the picture. Possibly not the best strategy.
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warmstrong1955
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Re: How to Get Hydraulic Coupler Off?

Post by warmstrong1955 » Mon Apr 09, 2018 7:56 pm

Not sure of the flavor of quick coupler you have, but looks like a Aeroquip FD45.
That is a very popular style.

If you get it good & clean...and de-oiled, you should be able to work the system, and see where it's leaking from....threads or the coupler. The coupler seals with an o-ring. I suspect you are correct, and it's the threads.
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SteveHGraham
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Re: How to Get Hydraulic Coupler Off?

Post by SteveHGraham » Mon Apr 09, 2018 7:59 pm

OK. You have to buy me a new tractor if I ruin it.
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warmstrong1955
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Re: How to Get Hydraulic Coupler Off?

Post by warmstrong1955 » Mon Apr 09, 2018 8:06 pm

Sure....put it on my tab!

If you are unfamiliar with such things....

Remove the hydraulic tank cap, and release any pressure before you start tearin' into it.
If the tank is higher than the quick-coupler, it will probably leak when you unscrew the quick-coupler. Gravity has no mercy, and it will make it difficult to put dope on the threads.
You can stop that with a vacuum on the hydraulic tank on the filler hole. If you use a shop vac, take care you don't start snorkeling up oil into it. They will make spectacular fire & flame.
I use a air-venturi vac.
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John Hasler
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Re: How to Get Hydraulic Coupler Off?

Post by John Hasler » Mon Apr 09, 2018 8:27 pm

Those couplers look ok to me but there's so much dirt I can't really guess what's happening. Clean the entire area up, run the machine, and inspect and photograph again (from several angles). I think your leak is down near the bottom of that assembly.

BTW those pipe threads used on ag machines are *supposed* to be NPTF, not NPT. Unfortunately, they are "interchangeable".

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Re: How to Get Hydraulic Coupler Off?

Post by Harold_V » Tue Apr 10, 2018 12:42 am

warmstrong1955 wrote:
Mon Apr 09, 2018 8:06 pm
Sure....put it on my tab!
No! Please, let me pay for it. :P

H
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steamin10
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Re: How to Get Hydraulic Coupler Off?

Post by steamin10 » Wed Apr 11, 2018 1:25 am

When working on mobile equipent and loaders, sometimes the assemblies must be taken down on the arms and the routing they take, to get to what you need. Bobcats and such compact loaders are notorious for no having any working room around fittings, so a sub assembly must be taken out to get to the crowded end. Another feature is the hard line getting a crack right where the first thread starts. It will weep forever. I used a liquid dealer for hydro lines, much like a loc tite product for bolts. Yu must wait to pressure the system tho for it to dry. Fittings are cheap enough, to replace suspect leakers. When the O-rings weep, it is time.
Good stuff.
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