Why are hoses hard to connect???

[Fuddy1952]

Today I went to connect my grapple hoses on. Anything hydraulic I use plastic end caps when not used. I always shut tractor off and relieve pressure by moving levers. I shop rag wipe everything clean. One went on easy as pie, I hold female ring back, slip in & release in seconds. Other I fought with 1/2 hr. No nicks or burrs, it's similar to picture but 3/4" so more holding balls around edge but same ball valve design.
Finally I removed female end and it went on & off easily, so I just coupled it back connected. No leaks.
What In the world makes them hard to connect at times? Doesn't make sense.

 

[Hay Dude]

Probably a change in temperature caused expansion in the implement.

 

[Fuddy1952]

What I can't understand how taking coupling off of hose end it goes on-off perfectly. And other one, same connectors goes on off easily. So simple but mind boggling!

 

[Hay Dude]

Heres what you do:
After you disconnect them from tractor, take the implement-side hoses and connect them. Then disconnect them. A little fluid will be released. Then reconnect them. Now you have a small expansion space for the next time the fluid expands from temp/pressure increases. It also keeps both your hydraulic ends nice and clean and protects them

 

[Cycledude]

The type of coupler in your picture can definitely be a pain sometimes.
One of my tractors has break away couplers and those are usually much easier.

 

[lpakiz]

The problem arises when you unhook the hoses while it's relatively cold, then attempt to rehook them in warmer weather. Simply, the oil expands a miniscule amount in the hose/cylinder and the tip will not push in to allow recouplong.
HayDudes method works if you remember to do it.
I don't force them very hard. If they won't latch, wiggle the joystick to make sure the tractor side is relaxed. Then, cover the hose end with a rag to prevent getting sprayed, and press the tip hard against something on the tractor, the floor, a tire, whatever. Get the tip to push in a bit.
If that doesn't work, loosen a convenient fitting on the offending hose, either end. Usually, i go for the cylinder end. A half turn will creat a little bit of "space" inside the hose. Press against the tractor or floor again to get that tip to move back a bit. Latch the coupler, then retighten the fitting. You won't lose more than a drop or 3 of oil.

 

[Fuddy1952]

That's what I ended up doing by removing coupler I guess. I could push ball in be hand and I always move joystick and spool valve. Strange how it wouldn't connect. I did get 90+% work done before dark and tomorrow supposed to rain.

 

[ericm979]

The type of coupler in your picture can definitely be a pain sometimes.
One of my tractors has break away couplers and those are usually much easier.

Those are break away type couplers, except they're not mounted.

Since the sleeve can go either way to unlock those are easier to connect- just hold the sleeve and push with the male end.

If the ambient temperature raised 20 degrees or more since the grapple was disconnected, the fluid in the grapple will have built up enough pressure to make it hard to connect.

I plug in a tee with a valve when I disconnect a hydraulic attachment.

 

[Cycledude]

Those are break away type couplers, except they're not mounted.

Since the sleeve can go either way to unlock those are easier to connect- just hold the sleeve and push with the male end.

If the ambient temperature raised 20 degrees or more since the grapple was disconnected, the fluid in the grapple will have built up enough pressure to make it hard to connect.

I plug in a tee with a valve when I disconnect a hydraulic attachment.

Those definitely are not break away couplers

 

[WranglerX]

Probably if you take a rag and cover ball and give it sharp rap against chassis or with hammer, it will release pressure and you may end up with small wet spot on rag, or not but pressure will be released... There is also some different tools to supposedly ease the problem, have seen discussion somewhere in the forum......

 

[MossRoad]

That's what I ended up doing by removing coupler I guess. I could push ball in be hand and I always move joystick and spool valve. Strange how it wouldn't connect. I did get 90+% work done before dark and tomorrow supposed to rain.

My machine is all hydraulic, so I deal with this fairly often. If I can't push on a connector, I shut off the machine. Grab the implement side of the connector. Take a rag, put it over the ball and connector. Take a flat punch and put it against the ball. Then give the punch a tap with a hammer. One drop of oil comes out, and that's usually enough to get it to connect easily.

If that doesn't work, I repeat the action on the tractor end of the connection. It has never failed to work.

I think it was Bird that may have told me about this maybe 20 years ago.

 

[JD 4520]

In an attempt to emphasize the prior two responses and not repeat, you are experiencing pressure in the line. To release the pressure, take the male end (with the exposed ball or point) and tap or simply push it against a hard flat surface on the tractor. Once that ball is pushed inwards, the pressure releases and you are then able to make the connection. A good firm ‘push’ of that ball should be all that it takes.

Let us know if this works or if you are still experiencing the problem.

 

[lpakiz]

DL,
I have had them build up so much pressure I couldn't get the tip to go in with a HAMMER!
I think the expansion of the fluid is multiplied by the volume, like everything thats in the hose and cylinder, and the bigger the cylinder, the higher the trapped pressure.
I like cycledudes idea of a coupler with a valve, but I suspect the same thing could be accomplished with a plugged spare tip. Usually, you can release a pressure locked male tip from the female. (uncouple) It's just that it won't re-latch with the tip pressure-locked.
And my experience is that if you can do the rag-and-press thing by hand, you could do it while coupling the real thing.
Since I discovered "bleeding" a couple drops of oil out of a handy fitting, that's become my "go-to" solution.

 

[JohnDeereJoey]

Between built up pressure in the lines, less than perfectly smooth/clean mating surfaces, and arthritis in my hands I was really struggling with couplers (Ag and Flat Face). This tool has really helped me. It's a bit bulky, but man does it work!

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[Fuddy1952]

That's what's weird: tractor not running, so no pump pressure. I move joystick different ways until bucket, grapple, etc doesn't move.
Connectors are spotlessly clean. I can push the male hose in with my finger...it's that easy. If I remove female end from the hose, no fluid comes out. Then I pull sleeve back & it goes on and off very easily.
So I just remove it...connect it then screw it back on hose fitting. It screws on easily since connector turns.
To me, although hoses are identical, the one female inside "plunger" (looks like a small nail head that pushes against ball) may be barely too long (?). I have extra connectors so I'll experiment tomorrow. Although it shouldn't easily connect together when off of the hose.

 

[Hay Dude]

You’re experiencing a spike in the pressure of your implement due to rapid temp increases. The hoses and cylinder have fluid in them that has no place to go. Therefore, a spring loaded coupler can’t push back into the fluid.
Just use the suggestions given and see what works best.
No reason to buy caps for the implement side if the connections can be simply attached to each other and that does a reasonable job of making reconnection to tractor easier.

 

[LD1]

Others explanations are spot on.

You can wiggle the joystick all you want, and that does relieve pressure on the tractor side but not on the implement side.

The implement hoses are under a little pressure because they they have warmed up since last disconnected. And wiggling the tractor joystick does nothing. By unhooking a coupler you relieved the pressure.

Hydraulic fluid isnt like air pressure. The fluid dont compress. So it could be under 1000PSI and relieving the pressure may be as little as loosing a drop of two of oil to bring it down to 0psi.

If the methods described above for unhooking dont solve your issues going forward, they do make couplers specifically designed to connect under pressure. You would need two sets and they are a little pricey. But would eliminate the fuss you are having.

 

[MossRoad]

...
Hydraulic fluid isnt like air pressure. The fluid dont compress. So it could be under 1000PSI and relieving the pressure may be as little as loosing a drop of two of oil to bring it down to 0psi.

...

That right there explains it best. Fluids cannot be compressed.

When you remove the connector, you may lose just one drop of oil. You may not. But you relieve the pressure immediately.

That, or as you've alluded to, maybe you have a faulty connector. Swap it with another one on the machine or a spare and see if the problem moves.

 

[bdhsfz6]

I made this tool from a cheap Harbor Freight welding clamp:

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I used an angle grinder to open the jaws enough to fit the slot in the hyd. coupler barrel



I use it to hold the fitting open while inserting or removing the coupler:



To relieve pressure bound hoses, I tap the ball end on a block of wood. It spits a bit of oil so keep a rag handy.

For implements with long hyd. hoses, I use a tee with hyd. couplers on the ends and a small relief valve in the center. I store the implement with the hoses connected to the tee. I use the valve to bleed off the pressure before installing.

 

[npalen]

DL,
I have had them build up so much pressure I couldn't get the tip to go in with a HAMMER!
I think the expansion of the fluid is multiplied by the volume, like everything thats in the hose and cylinder, and the bigger the cylinder, the higher the trapped pressure.
I like cycledudes idea of a coupler with a valve, but I suspect the same thing could be accomplished with a plugged spare tip. Usually, you can release a pressure locked male tip from the female. (uncouple) It's just that it won't re-latch with the tip pressure-locked.
And my experience is that if you can do the rag-and-press thing by hand, you could do it while coupling the real thing.
Since I discovered "bleeding" a couple drops of oil out of a handy fitting, that's become my "go-to" solution.

I think the expansion of the fluid is multiplied by the volume, like everything thats in the hose and cylinder, and the bigger the cylinder, the higher the trapped pressure.

Hmm--I wonder if that is actually the case. I can see the increase in volume being greater but wondering if the pressure increase is only proportional to the temp increase? The larger the initial volume of oil the more room it has to increase?