Hydraulic quick release coupling questions

[Meshna Dave]

Hi everyone, I'm new to the forum and I'd like to ask the TractorByNet community a few questions.
Together with some students I am analyzing the sector of quick couplings, in particular the hydraulic connections of agricultural and construction machinery and the problems related to them.

I would like to know in your opinion what are the main problems related to the connection / disconnection of the hydraulic lines between machines and equipment as well as the problems that may arise from the maintenance or replacement of quick couplings but more generally your experience in this regard.

Do problems like residual pressure building up in hydraulic hoses that prevents connection happen frequently? If so, how are they resolved? Or how do you manage the correct connection of the hydraulic lines of a vehicle with different tools? Which brands do you think are most reliable if you have already purchased these components? Etc.

Each comment could be valuable to help us better understand the dynamics of this sector so we thank you in advance for the help you are giving us, also I would like to assure that none of the given information will be used or published for commercial use but only for personal knowledge.

*I hope not to be off topic in this section

 

[Zebrafive]

I have a Faster brand single point/multi-coupler. In my case it's for 6 lines and connects/disconnects all at one time. It is used for my loader that has two extra (third function lines) in addition to the four for the loader. It works great! Because a lever is used to engage the couplers, pressure build up is not a problem.

The grapple that is used on the loader third function lines suffers from pressure build up in the lines when it is off. So putting it on is a problem. I use to loosen the male couplers on the grapple lines to relieve the pressure. A messy job. I finally installed two female couplers on the lid of a 5 gallon pail. As soon as I remove the grapple, I connect the lines to pail. Reconnection problem solved. There is a tool to depress the ball or poppet of the coupler tip to relieve the pressure, but I have not tried one. It takes very little pressure increase to make a coupler hard to connect. Just a temperature change will do it.


The other problem I have encountered on the tractor side couplers is leakage. I have had to rebuild the couplers on John Deere 2030 several times, but it is a 46 year old tractor and the couplers are an old, no longer used, design. The male tips are also an old, no longer used, design (John Deere only). These are not todays standard, so having both an older tractor and a newer one, they use two different coupler styles. Adapters or coupler changes are needed for using something set up for the old JD to use it on the newer tractor. I think now, couplers have been standardized.

 

[ericm979]

I plumbed a couple tees with couplers. The third leg of each tee has a valve and a cap. I plug the tee into an implement when I take it of. So when the oil expands because the temperature rises, I can let some out before detaching the tee and attaching the implement.

I bought some attach/detatch under pressure ag type couplers but the springs are so stiff on those that it's hard to get them on or off, even with no pressure. Without being mounted to a bulkhead it's nearly impossible.

I have the same problem with the flat face couplers I have tried. Even on a bulkhead they are tough to use. I like the idea of flat face couplers being easier to keep clean and not losing oil when detaching but they need to be easier to operate.

 

[hayden]

The biggest issue I have with couplers, and mostly with flat-face couplers, is connecting them when there is any pressure in either side of the connection. And there is ALWAYS pressure in one side or the other. Once in a while you might get lucky, but it's rare. I'm amazed manufacturers just continue to ignore this when it's not that hard to solve.

I have installed valves on the machine-side of both lines that open them to the tank, i.e. they relieve all the pressure in those lines. And rather that pissing hydraulic fluid all over the ground, is just runs back to the tank where it belongs. So far this has 100% solved the problem. However I'm expecting it won't quite be 100% since I think the couplers can get jammed by pressure in the implement side, and my relief valves won't help that, I don't think. Time will tell.

I think machine manufacturers should build such relief valves into their products, but who am I to say. They all say to shut down the machine and work the controls to release pressure, but it very seldom actually works, or works enough to make hookup easy.

 

[Michael In Tennessee]

The machine side should be simple. With the engine off, just cycle the loader control (or rear remote or 3rd function). They should drain to tank. It does work.

I have found for my grapple, I can connect the closing line with the grapple curled since gravity creates a slight vaccum. Then I uncurl and push the tine tips on the ground removing any pressure on the opening circuit.