Hydraulic connections won’t go on Grapple

[ericm979]

The fluid in the grapple expands and contracts as the temperature rises and falls. It expands more than I thought it would, and it does not take much pressure to make the quick connects operable.

I thought that connecting the grapple lines together would address it but that doesn't work for me. If the temp rises more than about 10 degrees between when I disconnected the grapple to when I want to connect it again the grapple QCs that are connected to each other won't disconnect.

My solution was to make a device with a tee, two quick connects and a ball valve. The grapple lines get plugged in when I remove the grapple. When it's time to put the grapple on I let the pressure out with the valve, then disconnect the device and plug into the tractor. I made one for the backhoe as well. The ball valve has a cap on the end so dirt won't get in there and potentially into the hydraulic system.

 

[bdhsfz6]

For some reason, my grapple is the only one of my hydraulic implements that has this issue. I made a simple "T" with QR connectors and a bleeder valve. I leave it connected to the grapple when not in use and bleed off any pressure before reinstalling. Solves the problem completely.

To further aid in connecting and removing these QR connectors, I made this tool from a cheap Harbor Freight welding clamp:

I ground off the clamp tabs to fit the notch in my Pioneer QR fittings. Makes the process much easier.

 

[bill9068]

Turn the key on but don’t start, press your grapple buttons, this relieves the pressure then uncouple the connection.

 

[DieselBound]

I try to keep the grapple opened up a bit when disconnecting. That allows me to, if needed, stuff a hydraulic or a screw jack between the jaws in case I have to force pressure in the OPEN line/circuit. I'm thinking that I'm doing less of this of late: likely similar to burning incense...

It seems that no one trick/approach seems to work in all cases/times. I have flat-faced connectors (these seem to be more or a pain). Most success I have seems from shoving a small socket (a bolt would work) that'll fit inside the female connector (grapple hose end) and whack it with a hammer ; this releases pressure (and, of course, fluid- use rags to subdue the fleeing fluid!).

I can also run across recalcitrant AG couplers on the read. These are easier to relieve pressure on (smack mail connector straight into flat surface- these couplers will tend to leak a lot more fluid, and do so readily/quickly, so once again- use rags!).

 

[oosik]

I don't know what causes the problem. I have a quick and easy "fix". I have a six inch chunk of 1/2" diameter hard nylon rod. Rod on the ball - tap on the rod end with my smaller dead fall hammer. Pressure is relieved - connection is easy.

I wrap an old shop rag around the rod and hydraulic fitting. Hold it all together in my left hand - tap the rod with the dead fall hammer that's in my right hand. The rag absorbs any hydraulic oil that will squirt out.

 

[TractorGuy]

The problem is pressure build up from the trapped fluid getting hot.

If you have ball type ends you would want to use something soft to release the pressure.

The typical ISO type ag connector has a tip protruding so the seat won't get damaged by tapping it directly on a piece of metal. I don't even try connecting mine without smacking it on the frame one time first.

 

[DieselBound]

The problem is pressure build up from the trapped fluid getting hot.

If you have ball type ends you would want to use something soft to release the pressure.

The typical ISO type ag connector has a tip protruding so the seat won't get damaged by tapping it directly on a piece of metal. I don't even try connecting mine without smacking it on the frame one time first.

If it's a hot fluid issue, and I think you're on to something here, then is it an issue of unhooking when the fluid is hot or? I'm just musing here: my brain cells are currently taking a nap- I'll leave this for others to ponder...

 

[LD1]

I try to keep the grapple opened up a bit when disconnecting. That allows me to, if needed, stuff a hydraulic or a screw jack between the jaws in case I have to force pressure in the OPEN line/circuit. I'm thinking that I'm doing less of this of late: likely similar to burning incense...

It seems that no one trick/approach seems to work in all cases/times. I have flat-faced connectors (these seem to be more or a pain). Most success I have seems from shoving a small socket (a bolt would work) that'll fit inside the female connector (grapple hose end) and whack it with a hammer ; this releases pressure (and, of course, fluid- use rags to subdue the fleeing fluid!).

I can also run across recalcitrant AG couplers on the read. These are easier to relieve pressure on (smack mail connector straight into flat surface- these couplers will tend to leak a lot more fluid, and do so readily/quickly, so once again- use rags!).

Keeping it open a bit makes the weight of the lid increase the pressure in the line.

Shut tractor off and bleed everything good. This should make the lid all the way closed.

Yes unhooking when the fluid is hot helps. If you unhook when everything is cold...or immediately pull it out of barn and unhook....then the sun beats down on all the black cylinder and fittings before you try reconnecting....now you have issues.

 

[DieselBound]

Keeping it open a bit makes the weight of the lid increase the pressure in the line.

Shut tractor off and bleed everything good. This should make the lid all the way closed.

Yes unhooking when the fluid is hot helps. If you unhook when everything is cold...or immediately pull it out of barn and unhook....then the sun beats down on all the black cylinder and fittings before you try reconnecting....now you have issues.

The key part was "a bit." It's hard to get something in to pry it OPEN if you don't have a space to put a jack in. We don't know, well, I don't know, which direction it is being over-pressurized. Keeping it open "a bit" allows for EITHER opening or closing. I like to keep my options open; or, would that be keeping my options closed?

 

[TractorGuy]

If it's a hot fluid issue, and I think you're on to something here, then is it an issue of unhooking when the fluid is hot or? I'm just musing here: my brain cells are currently taking a nap- I'll leave this for others to ponder...

In my case I think it builds pressure from sitting in the sun. I leave mine outside.

I move my loader control in every direction with the diverter on and off to relieve all pressure before disconnecting.

I suspect that I could just hook up on a cold morning but I have got in the habit of tapping the male end before I try.