Front hydraulic couplings for grapple not releasing pressure

[RinconVTR]

Strange thing. The grapple fully closed, power off, actuate the hydraulic lever to what I thought would relieve hydraulic pressure.

Remove the two quick connect hoses for the grapple, then try to reconnect...no-go. Pressure remains in (apparently) the grapple side.

Any ideas to easily address this?

 

[Sysop]

Wrap the side with the ball in a rag and press the ball against something to relieve the pressure.

Basically you've disconnected it at a lower temp than you're trying to connect it. Higher temps increase pressures. It's mostly inevitable. Best option is connect the two QDs together when you take your grapple off. If pressure has increased while it is setting, you'll relieve enough pressure disconnecting the two, that attaching them to the tractor will be easier.

If possible, attaching the two QDs on the loader together allows fluid to pass through, so if you accidently bump the switch you don't load one of the lines up with pressure.

 

[Oldtractorfixer]

I can't tell you how many times I've been sprayed with hydraulic fluid trying to do this. Hit the male end on the loader frame to relieve pressure and spray everywhere not just me but the loader etc. So what to do. I get/carry a cresent wrench, crack the hydraulic line at the cylinder, let it leak the pressure off in a dribble and put it together.

 

[k0ua]

Best option is connect the two QDs together when you take your grapple off. If pressure has increased while it is setting, you'll relieve enough pressure disconnecting the two, that attaching them to the tractor will be easier.

After I started doing this, I have never had a problem connecting up. ^

 

[Sysop]

I can't tell you how many times I've been sprayed with hydraulic fluid trying to do this. Hit the male end on the loader frame to relieve pressure and spray everywhere not just me but the loader etc. So what to do. I get/carry a cresent wrench, crack the hydraulic line at the cylinder, let it leak the pressure off in a dribble and put it together.

A rag is easier to carry around/keep handy, and captures any spray. No dribbles to hunt a rag to cleanup after also. It is simply much faster to wrap and tap than muck around with wrenching the end loose. The whole purpose of QDs is so wrenches aren't needed to plumb lines together.

 

[N2DFire]

Strange thing. The grapple fully closed, power off, actuate the hydraulic lever to what I thought would relieve hydraulic pressure.

Remove the two quick connect hoses for the grapple, then try to reconnect...no-go. Pressure remains in (apparently) the grapple side.

Any ideas to easily address this?

I think we're all making a couple assumptions
1) That you're issue is on the tractor side and not the grapple side.
2) That you're using a rear remote to operate the grapple.

If you are using a diverter or 3rd function valve then having the power off is most likely not letting them activate to relieve pressure in the grapple circuit.

 

[Sysop]

Can't speak for anyone else, but I never assumed either of those things.

 

[ovrszd]

His problem is on the attachment side.

Activating the circuit before disconnecting won't fix this problem.

Connecting the two hoses together helps slightly. But this is only possible if the QC's are setup one male one female at the attachment side.

I'm very conscious of the temps when I unhook, rehook. Direct sunshine will also cause this problem. Flatface couplers are worse because they are designed to not leak during connection.

 

[ovrszd]

Can't speak for anyone else, but I never assumed either of those things.

Me too.

Or is it me neither.

I always get those confused.

 

[k0ua]

One thing I also do is immediately after taking the grapple off (while the fluid is hot) is to couple the male and female QD's together and then uncouple them. This will let a little fluid leak out. Then I couple them again. Now there is a "deficit" of fluid in the lines. Even if it cools down and then heats up due to a rise in temp, there will be a little space for expansion. And it is not likely that it will get hotter than the fluid was while the tractor and grapple was in use. In any case, I NEVER, EVER have a problem with connecting the lines back because of a pressure rise in the lines.

 

[ovrszd]

Yep James, uncoupling hot is the best protection if possible.

 

[N2DFire]

Remove the two quick connect hoses for the grapple, then try to reconnect...no-go. Pressure remains in (apparently) the grapple side.

Ok - Mea Culpa - I missed this part when I read it.

But I stand by my statement that it still could be he's not really reliving any pressure like he thinks IF he's using a Diverter or 3rd function valve and operating it with the power off.

Especially so if we assume (yea I know I'm already in the hole here for that) he is doing all this immediately as a trouble shooting series.

The grapple fully closed, power off, actuate the hydraulic lever to what I thought would relieve hydraulic pressure.

Remove the two quick connect hoses for the grapple, then try to reconnect

If so there's no time for thermal expansion / contraction in the grapple lines therefore another potential answer is that there is still residual pressure in the lines because he isn't relieving it like he expects he is.

I apologize if I came across as arguing or contradicting what you guys offered up. Just simply trying to trouble shoot & provide all possible options to look at. It's the old school medic in me. Differential Diagnosis - Throw every possible answer into the funnel and then start taking out what doesn't fit as you discover more symptoms.

Until the OP offers up more information (symptoms) on his process - this (at least to me) still remains a viable answer to the problem.

And FWIW - I agree with the coupling the hoses on the grapple together. I keep mine that way for that & to keep them clean and I have yet to have an issue either.

Me too.

Or is it me neither.

I always get those confused.

I usually say Me too neither just to be safe.

 

[ovrszd]

No apology needed here. Just discussing a problem and searching for a solution.

 

[DieselBound]

Well, as a newbie to stuff like this, I too have this question/problem. I recently hooked up some hydraulic lines for my grapple (everything is new to me, even the tractor) and when I disconnected the grapple I went to connect the two lines on the grapple side together and NO GO! Flat-face connectors, 1/2". I'm not exactly superman, but I'm no weakling either, but no way was I able to push the two connectors together. If I'm reading correctly, one should do this after things are warm: I was doing this cold- tractor and all. Learned something new today!:thumbsup:

 

[LD1]

Flatface couplers are worse because they are designed to not leak during connection.

Exactly why I got rid of the flat face couplers. I couldnt get them to re-hook no matter what. I would shut tractor off, turn key on (to energize diverter), and cycle the stick several times. Take them apart and couldn't reconnect even immediately after taking them apart. With my diverter being on the lift/lower circuit, I have a rubber band that lives around the joystick. Just slide it up over the trigger and detent into float.

Got tire of messing with it, and adding a front snow plow, I just swapped them to 1/4" 7241-B couplings to match what I run on snow plows.

As for the OP, its more cost, but they do make connect-under-pressure couplings that should solve the issues.

 

[ovrszd]

Well, as a newbie to stuff like this, I too have this question/problem. I recently hooked up some hydraulic lines for my grapple (everything is new to me, even the tractor) and when I disconnected the grapple I went to connect the two lines on the grapple side together and NO GO! Flat-face connectors, 1/2". I'm not exactly superman, but I'm no weakling either, but no way was I able to push the two connectors together. If I'm reading correctly, one should do this after things are warm: I was doing this cold- tractor and all. Learned something new today!:thumbsup:

What you did was release the couplers with a "load". To prevent that you should shut the tractor off, then cycle the grapple controls to release any pressure, then disconnect.

Most common problem that is being discussed here is pressure that builds in the grapple system after it has been disconnected. Such as from heat expansion that occurs because of uncoupling during cool ambient temps then trying to recouple during warm ambient temps.

 

[DieselBound]

What you did was release the couplers with a "load". To prevent that you should shut the tractor off, then cycle the grapple controls to release any pressure, then disconnect.

Most common problem that is being discussed here is pressure that builds in the grapple system after it has been disconnected. Such as from heat expansion that occurs because of uncoupling during cool ambient temps then trying to recouple during warm ambient temps.

I only recall operating the valve lever, and dropping the lid (which had been parked open). Didn't seem like an issue disconnecting the hoses, didn't feel like there was much pressure.

 

[ovrszd]

I only recall operating the valve lever, and dropping the lid (which had been parked open). Didn't seem like an issue disconnecting the hoses, didn't feel like there was much pressure.

If you are running your grapple with a simple mechanical hydraulic valve/lever, that should have done it. If you are running your grapple thru a diverter or electric over hydraulic 3rd function valve you would need power to the electrical switch before operating it to release pressure. All of this done in either case with the tractor shut down.

 

[DieselBound]

Richard, yeah, I'd read ahead of time on how to deal with this and I thought that I had done it properly, which is why I was a bit perplexed.

 

[kevin37b]

Yes tractor not running , but key on .