Fix for Pressure Bound Hydraulic Couplers ?

bdhsfz6 · Nov 29, 2017

All the Kubota dealers I've dealt with over the years seem to prefer flat faced hyd. couplers on the 3rd function valves and FEL mounted implements they sell. IMO, flat faced couplers have some advantages. They don't load up with debris, don't leak much oil during connection, are easily cleaned with a rag and don't require protector caps.

They are expensive though and are prone to pressure binding. The pressure must be completely relieved on both sides. For my Kubotas, Relieving the pressure on the tractor side requires lowering the FEL to the ground, shutting down the tractor and working the FEL valve in all four directions while holding the 3rd function valve open. I sometimes have to do this multiple times.

My implements are more of a challenge. Even though the pressure is relieved after disconnecting, it always builds again due to temperature changes, cylinder bleed down or movement of the implement itself. Most of the time, I have to loosen one or both of the hose fittings to bleed the pressure off when connecting again. To me, this is a PIA and defeats the purpose of the leak free coupler design.

Am I missing something here? Do other users of flat faced couplers have similar problems?

I've been thinking of switching to the Pioneer style with pressure check on both sides:

Before I spend considerable $$ to convert two tractors and several implements, I'd like to know if they will be any better. I'd appreciate the opinion of others here.

There is always the option of going to the Pioneer style with no pressure check on the male side like those used on rear remotes. The oil loss is considerable with this type though.

I'm also considering adding a tee in the implement hoses with a valve such as this one to bleed off pressure:

1/4 NPT 5 GPM Prince WFC-4 In-Line Flow Control | Prince Mfg | Brands | www.surpluscenter.com

Thanks in advance for any suggestions.

Fallon · Nov 29, 2017

You only need to turn off the tractor & actuate the 3rd function each way, not the whole loader. That usually is enough for me. Plan B is a wrench & cracking the QDs on the the impliment. Disconecting an imiments when it's hot & connecting it when it's cold helps, but isn't always possible.

I've thought about switching over to connect under pressure QDs, but they are even more expensive than flat face from what I see. Usually have a threaded fitting of some kind to give you a mechanical advantage to push the connectors together overcoming any pressure, from what I've seen. I don't think the AG style will be any better than flat face. I couldn't plug my TnT cylinders in when an impliment was hanging on the 3pt. Had to set it down, relieving pressure & they finally hooked up. Decent OEM Kubota AG style QDs there

bdhsfz6 · Nov 29, 2017

Fallon said:
You only need to turn off the tractor & actuate the 3rd function each way, not the whole loader. That usually is enough for me. Plan B is a wrench & cracking the QDs on the the impliment. Disconecting an imiments when it's hot & connecting it when it's cold helps, but isn't always possible.

I've thought about switching over to connect under pressure QDs, but they are even more expensive than flat face from what I see. Usually have a threaded fitting of some kind to give you a mechanical advantage to push the connectors together overcoming any pressure, from what I've seen. I don't think the AG style will be any better than flat face. I couldn't plug my TnT cylinders in when an impliment was hanging on the 3pt. Had to set it down, relieving pressure & they finally hooked up. Decent OEM Kubota AG style QDs there

Not sure why but relieving the pressure on just the 3rd function valve doesn't do it on either of my Kubotas. Both have W&R Long 3rd function valves.

I read a post in another forum about someone solving the problem by shutting off the tractor and holding the 3rd function valve open with a rubber band on the switch. Might try that one. Still, the implement side is more of a PIA than the tractor.

dstig1 · Nov 29, 2017

I have a longstanding issue with this on my current tractor and my previous one on the third function. Also flat face couplers. I can do anything i want regarding releasing the pressure and if i am lucky I can connect one of the two couplers. I made a pressure reliever out of a couple of pipe fittings and one each flat face coupler (open to air). If I cannot get a coupler to connect, i use this to let out some pressure. I also often put a quick grip clamp around the fitting when i can get it partially together then cycle the lever to keep releasing the pressure bit by bit and alternating by tightening the clamp. Eventually it will make it home, but this is a major PITA for trying to hook up the grapple as it adds a good 15 min just making the hydraulic connections sometimes. I even spent extra money on the flat face "connect under pressure" couplings. No effect i could see!

mopardude318 · Nov 30, 2017

I've tried those connect under pressure flat face couplers available from Discount Hydraulics. I just used them actually last week. The truth is, is that I haven't noticed anything different, it was still difficult to connect, and I had to relieve the pressure from third function with the tractor off. Another thing, maybe I got a bad set from Discount Hydraulics, but they leaked right from the get go. I noticed they said "made in china" on the side...Maybe that has something to do with the leaking problem? I was a certainly disappointed once they constantly seeped while in use, since I paid $90 bucks to my door for the set.

4HTF4-P-SET | Set of 1/2" Connect-Under-Pressure ISO 16028 Quick Disconnects

4570Man · Nov 30, 2017

I find them a little better. You can hit the male coupling against the loader and it will depress the button and let fluid squirt out. Sometimes it'll take like that. Other times you'll need a punch and hit the female side too. I've found that if you equalise the implement ( my 3rd function is 12 volt so shut off the tractor, turn the key back on, and cycle the button several times) it'll usually go back on with minor issues unless there's been a temperature increase since it was disconnected.

bcp · Nov 30, 2017

One man's fix:

http://www.tractorbynet.com/forums/build-yourself/305952-flat-face-hyd-coupling-pressure.html

Bruce

lennyzx11 · Nov 30, 2017

I put a male and female on each implement and on the tractor.
By hooking the implements hoses together when off the tractor, I haven't had to fight that connection anymore.
I used to just leave the tractor side loose but after using the aforementioned practice of smacking the ball of the fitting to relieve pressure, I find that the fitting will leak fluid on the garage floor overnight.
So now those two lines also get looped together also which gives an advantage of keeping the internals of the QDs clean.

Wagtail · Nov 30, 2017

I'm glad that the OP included the names/terminology of the couplers he has and is considering (different countries = different words). I've not seen these 'flat' versions myself.

I do have the "pioneer" type that he is considering and the result will be the same. I, too, have to relieve the pressure (shut down the engine and move the joystick in all four planes + the 3rd function button in two planes) to connect/disconnect. I do not lose any hydraulic fluid using this method.

It took many attempts and too many swear-words until a thread on TBN twigged me to this fact.

mopardude318 · Nov 30, 2017

I might break down and try these made by Holmbury, I have their standard 'HQ' couplers on my auger, which appear to be real nice.

Eliminate pressure in hydraulic systems with flat-face couplings - YouTube

rswyan · Nov 30, 2017

bdhsfz6 said:
... My implements are more of a challenge. Even though the pressure is relieved after disconnecting, it always builds again due to temperature changes, cylinder bleed down or movement of the implement itself. Most of the time, I have to loosen one or both of the hose fittings to bleed the pressure off when connecting again. To me, this is a PIA and defeats the purpose of the leak free coupler design.

Am I missing something here? Do other users of flat faced couplers have similar problems?

I actuate the control valve as I am attempting to insert/connect the fitting (SS/FF couplers)

Works for me every time.

bdhsfz6 · Nov 30, 2017

mopardude318 said:
I've tried those connect under pressure flat face couplers available from Discount Hydraulics. I just used them actually last week. The truth is, is that I haven't noticed anything different, it was still difficult to connect, and I had to relieve the pressure from third function with the tractor off. Another thing, maybe I got a bad set from Discount Hydraulics, but they leaked right from the get go. I noticed they said "made in china" on the side...Maybe that has something to do with the leaking problem? I was a certainly disappointed once they constantly seeped while in use, since I paid $90 bucks to my door for the set.

4HTF4-P-SET | Set of 1/2" Connect-Under-Pressure ISO 16028 Quick Disconnects

Thanks for the info on the connect under pressure flat face fittings. My dealer doesn't think much of them either. Before spending that kind of money, I'd invest in one of these tools:

Amazon.com: Flush Face Coupling - Hydraulic Pressure Relief Tool - use with 1/2 inch male coupling: Home Improvement

For flat face.

Amazon.com: Poppet Check Coupling - Hydraulic Pressure Release Tool - use with 1/2 inch male coupling: Home Improvement

For Pioneer.

On a couple of my implements, relieving the pressure on one hose doesn't do it on the other. It isn't clear how either of these tools deal with depressurizing the female coulper.

mikester · Nov 30, 2017

Has anyone tried the new M62 MULTI-COUPLER SYSTEM?

My solution has been to power off the tractor and leave the hydraulic remotes on float to relieve the pressure in the implements. The biggest problem I find is when the implement has been sitting outside in the sun especially if I disconnected it earlier in the morning when it was cool out.

4570Man · Nov 30, 2017

Some of these solutions look like more work than just loosing the line.

Industrial Toys · Nov 30, 2017

I use dozens of the FF couplers and hate them. Always having to shut off the machine and relieve pressure. They are supposed to be coupled or uncoupled under pressure, but this seems to be nonsense.

An implement sitting unattached that has been subjected to temperature changes can also get locked up. You must break a line and spill fluid to remedy this.

The couplers are also very subject to damage from dropping on concrete. Sometimes you can't even see any damage, but they are garbage.

Also, you can't go anywhere below freezing without carrying a propane torch. Any little frozen moisture, will prevent them from operating.

Also, some brands don't work as well with some other brands.

Did I mention, I hate them?,

bdhsfz6 · Dec 1, 2017

lennyzx11 said:
I put a male and female on each implement and on the tractor.
By hooking the implements hoses together when off the tractor, I haven't had to fight that connection anymore.
I used to just leave the tractor side loose but after using the aforementioned practice of smacking the ball of the fitting to relieve pressure, I find that the fitting will leak fluid on the garage floor overnight.
So now those two lines also get looped together also which gives an advantage of keeping the internals of the QDs clean.

When using this procedure, I find it's sometimes difficult or impossible to separate the male and female FF QD's on a pressure bound implement that has been stored for a time. On the rare occasion I am able to get them apart, there is often enough residual pressure in the lines to prevent connection to the tractor. This just doubles the frustration for me anyway.

I guess it depends on individual conditions though and if it works for you, then you've found a solution. Thanks for posting!

bdhsfz6 · Dec 1, 2017

mopardude318 said:
I might break down and try these made by Holmbury, I have their standard 'HQ' couplers on my auger, which appear to be real nice.

Eliminate pressure in hydraulic systems with flat-face couplings - YouTube

Depending on price, these could be an effective solution. Two fittings might be required for implements with two pressure bound hoses though. Thanks for the link.

moship · Dec 1, 2017

I was thinking of making up extra hoses so they could be connected to the implement during storage as in creating a jumper hose. This way the fluid could move freely between each end of the cylinder when implement is stored. There would still be fluid loss (what's inside the jumper hose), but it would prevent having to crack the fittings.

Do you think this would work?

Fallon · Dec 1, 2017

moship said:
I was thinking of making up extra hoses so they could be connected to the implement during storage as in creating a jumper hose. This way the fluid could move freely between each end of the cylinder when implement is stored. There would still be fluid loss (what's inside the jumper hose), but it would prevent having to crack the fittings.

Do you think this would work?

If you had a stubby hose with a male & female flat face at each end it would leave you in a similar place. Unless you put in a small valve on that hose you could crack to drain off a little pressure/fluid. In which case that would likely do the trick.

Fallon · Dec 1, 2017

Industrial Toys said:
I use dozens of the FF couplers and hate them. Always having to shut off the machine and relieve pressure. They are supposed to be coupled or uncoupled under pressure, but this seems to be nonsense.

An implement sitting unattached that has been subjected to temperature changes can also get locked up. You must break a line and spill fluid to remedy this.

The couplers are also very subject to damage from dropping on concrete. Sometimes you can't even see any damage, but they are garbage.

Also, you can't go anywhere below freezing without carrying a propane torch. Any little frozen moisture, will prevent them from operating.

Also, some brands don't work as well with some other brands.

Did I mention, I hate them?,

But do any other style of couplings generate less hate?