Relieving Hydraulic Pressure - Best Method?

[Osconda]

When I bought my tractor I also got a root grapple for my loader. Picture of it here: http://www.rootgrapple.com/GRAPP40.jpg
It's a piece of cake to quick detach my loader bucket and attach the root grapple but the hydraulics is a different story. Here's the details....

When I received the grapple it came with a set of hoses already attached. These hoses have threaded fittings where they connect to the frame of the grapple and the other end of the hoses had a quick disconnect fitting. In order to get my rear hydraulics connected to the grapple, I went down to a local hydraulic shop and had two extension hoses made to length with quick disconnect fittings that matched the existing hoses that came with the grapple. I picked up a set of quick disconnect fittings at my dealer that match my tractor's rear remotes and installed them on the other end of the "extension" hoses.

The quick disconnect fittings that attach to the tractor have a small bump on the end but the fittings that came on the grapple are flat. More on this later.

If I'm switching from the root grapple to the material bucket I don't have any trouble taking the hydraulic fittings apart. Switching these two takes about 3 minutes.

If I'm switching from the material bucket to the root grapple, somehow there is some built up pressure left in the cylinders and there is no way to connect the grapple hoses to the tractor hoses without taking a wrench and loosening the threaded connections. It doesn't seem to matter whether the cylinders are retracted or not. There is no way to relieve pressure on the flat quick disconnect fittings on the grapple, like you can on the tractor fittings.

I was wondering if there was some kind of valve I could put between the threaded fittings and the quick disconnect fittings so I could just quickly open and close to relieve the pressue. The valve would have to be able to handle the 2500 PSI working pressure. Or perhaps somebody has some other creative idea on how to solve my problem.

 

[Soundguy]

Lots of people report this with loaders and QD's.. they simply set it down.. kill the tractor.. then run the spool controll all around till the hyd pressure is released.

The other non-scientific method was discussed as poppint the tip o fthe qd with a wrench to make it squirt some of that pressure out.

Soundguy

 

[RobS]

Like Soundguy said, use the "other non-scientific method". If you do though, be sure to wrap a rag around the end of the hose. Keeps things clean but most importantly, protects you from that stream of high pressure hydraulic fluid /forums/images/graemlins/smile.gif

 

[Osconda]

</font><font color="blue" class="small">( Lots of people report this with loaders and QD's.. they simply set it down.. kill the tractor.. then run the spool controll all around till the hyd pressure is released.

The other non-scientific method was discussed as poppint the tip o fthe qd with a wrench to make it squirt some of that pressure out.

Soundguy )</font>
There is no tip on the end of the quick couplers, they are flat. The hydraulic remote only has an up and down movement and I have tried working this before I disconnect the grapple but it doesn't make a difference.

 

[PineRidge]

Can you take a picture of the disconnects and possibly post it here for further advice?

Before I disconnect our grapple I slightly open it (helps so the pressure doesn't build against the bucket) then pull the disconnects apart. Hooking it back up is simple if I follow my own instructions.

 

[MadReferee]

Do your couplers look like the one in the attached picture?

If so then press in on the male end's flat surface to relieve pressure in the hose.

Also make sure you are putting these flat male couplers into female QD's that are specially designed for them. The ball couplers and these drybreak flat ones are not always compatible.

 

[Osconda]

No the couplers don't look like the picture. I'll take a picture and post it later. Also, the couplers do match up correctly and I don't have any trouble connecting them, once the pressure is relieved.

 

[jmc]

I've got the same problem with my flat faced couplers on a tracked loader. I've been going back and forth between tree shear and grapple and it takes about 15 minutes/per change. I'm hoping its only a damaged coupler from an incident involving too short of a hose on a new attachment. In the meantime, I made a device to depress both couplers on each side of the connections. I also made a handle to get a better grip on the hose connectors.

I don't think it takes very much external force on the grapple to develop enough pressure that you can't overcome it with hand force. Like the grapple arms settling in the dirt after you disconnect it. Someone else mentioned sitting out in the sun could cause it. Pineridge's trick of leaving it open may work because his grapple arm is light but it would be the wrong thing to do on mine.

Also, did you check your manual about how to relieve residual pressure on the loader side?

John

 

[Osconda]

</font><font color="blue" class="small">( I've got the same problem with my flat faced couplers on a tracked loader. I've been going back and forth between tree shear and grapple and it takes about 15 minutes/per change. I'm hoping its only a damaged coupler from an incident involving too short of a hose on a new attachment. In the meantime, I made a device to depress both couplers on each side of the connections. I also made a handle to get a better grip on the hose connectors.

I don't think it takes very much external force on the grapple to develop enough pressure that you can't overcome it with hand force. Like the grapple arms settling in the dirt after you disconnect it. Someone else mentioned sitting out in the sun could cause it. Pineridge's trick of leaving it open may work because his grapple arm is light but it would be the wrong thing to do on mine.

Also, did you check your manual about how to relieve residual pressure on the loader side?

John )</font>

The grapple was designed with a skid steer compatible plate so I guess the flat faced couplers are common to a skid steer loader.

I'm thinking that the two grapple arms are heavy enough (3/8" steel) to put back pressure on the cylinders. It's impossible to pull back on both grapples and then try to make the connection (requires 4 hands). I make it a practice to keep the cylinders retracted( grapple open) so the cylinders aren't exposed to the weather if I don't use if for an extended period.

JMC, I'd like to see a picture of the gizmo you made to help you make the connection.

I accidently disconnected the grapple once with it closed(cylinders extended) and I had to let a lot of fluid out to make the connection.

I've got 60 hrs. on my tractor now and probably half of those have been using the root grapple. It's a great tool but it sure would be nice if the couplers really were "quick".

 

[Osconda]

PineRidge,

Here's a few pics of the couplers.