Having bad luck with Dixon hyd. couplings

[t320pilot]

This is really strange that 2 in a row quick couplings failed with only a few changing out of attachments. Went from bucket to grapples and back three times and always made sure everything is clean before hookup. Been running equipment for 40 years and never had the same o-ring on the same fitting fail like this especially made in the USA. Of course it only happens on the weekend when most parts stores are closed.
Anyone else had bad luck with Dixon quick couplings? Coupling on the left was replaced a few days ago, then the right one went bad today.

 

[countrybumpkin]

I’d be looking at the male ends, something with it has to be letting that happen.

 

[npalen]

I had a very similar issue with a quick coupler last summer and blew a couple orings in the same coupler within a short period of time. I suspect that it was pressure buildup in the line due to thermal change or possibly due to leakage thru a valve causing pressure intensification between the rod and base side of the cylinder.
A pressure spike due to something similar might be happening in your case.

 

[t320pilot]

The male ends are fine. It has to be an o-ring problem.

I’d be looking at the male ends, something with it has to be letting that happen.

 

[t320pilot]

They should be able to handle temp changes from 70 - 30f without any issue at all. Went years and years running other equipment and never had the same problem unless the coupling was really old and worn out. They should last a lot more than a few change outs.

I had a very similar issue with a quick coupler last summer and blew a couple orings in the same coupler within a short period of time. I suspect that it was pressure buildup in the line due to thermal change or possibly due to leakage thru a valve causing pressure intensification between the rod and base side of the cylinder.
A pressure spike due to something similar might be happening in your case.

 

[npalen]

Are these the couplers for your grapple? If so, what type of valve are you using for the third function? Is it a selector type valve by chance?
The reason I'm asking is that in my case the failed coupler was part of the third function and I believe that leakage thru the selector valve was causing pressure intensification and blowing the oring. This occured when the tractor was parked.
I replaced the oring but the new oring failed in a short time. Replaced it again and has held fine now for several months.

Edit: I don't know what's causing your problem--just relating my experience.

 

[ptsg]

You don't need to replace the whole coupling, you can replace the O-ring and backing ring inside.

It looks to me that the male coupling doesn't have quite the right diameter for that female coupling. Are they a matching set? As in the same brand and model.

 

[t320pilot]

Are these the couplers for your grapple? If so, what type of valve are you using for the third function? Is it a selector type valve by chance?
The reason I'm asking is that in my case the failed coupler was part of the third function and I believe that leakage thru the selector valve was causing pressure intensification and blowing the oring. This occured when the tractor was parked.
I replaced the oring but the new oring failed in a short time. Replaced it again and has held fine now for several months.

Edit: I don't know what's causing your problem--just relating my experience.

I have a W.R Long kit that was installed at the Kubota dealership when I bought the tractor new in July 2018. One of the female end o-rings failed at the grapple hose end and the other at tractor hose end where it connects to the grapple.

 

[t320pilot]

You don't need to replace the whole coupling, you can replace the O-ring and backing ring inside.

It looks to me that the male coupling doesn't have quite the right diameter for that female coupling. Are they a matching set? As in the same brand and model.

They are a matching set, same brand and size, that's what is strange. I'm also at engine idle when swapping out attachments.

 

[ptsg]

I'm now thinking that you might have been disconnecting the couplers under pressure. That moment you push the collar back to disconnect, the oil under pressure will get behind the O-ring causing it to fail.

Before disconnecting the couplers, try to turn off the engine, leave the key in On position without starting the engine and cycle the 3rd function valve to relief the pressure.

I'm assuming here you have a solenoid valve for the 3rd function. These allow for full flow and pressure once you press one of the buttons, which will leave one line on the grapple cylinders under full pressure at the end of the stroke. Hence my theory about the blown o-rings.