quick connect tip & warning

[TomG]

Fairly new operators may not have experienced the hydraulic quick connect that, when disconnected, can't be reconnected. Most often, the problem is due to pressure in the male connector line. Pressure can result from disconnecting a line on a cool day and reconnecting it on a hot sunny day. Pressure can be high enough so the ball bearing seat on the end cannot be depressed easily to seat the fitting. Solution for this is to place the ball bearing between a rag and a hard surface and push to depress the ball.

The warning is that pressure can be so high that the ball cannot be depressed. I think I did this number to myself when I disconnected the bucket curl to use for my hydraulic top link. I wanted the bucket curled up to hold ballast, so I curled the bucket up to the max and then disconnected the hoses. I doing so, I probably left the line with 'relief-valve' pressure in it. No way I could push in that ball. I ended up loosening a fitting with wrenches to bleed off the pressure. Anyway, it's a real good idea to set everything on the ground, turn off the tractor and work all levers both directions before disconnecting hoses.

Well, I guess I'm on a tips roll, here's another. I was having a devil of a time bleeding the fuel line after a filter change. The are two bleed vents on the filter bowl that I was bleeding, and bleeding, and bleeding. I was worried that I might have to loosen the injector lines, but then I noticed that the line from the filter to the injector pump has an upward bow and went into the pump through a banjo fitting. Well, I thought, there's a good place for air, so I loosened the banjo fitting and ran some fuel through it, and was rewarded with a little hiss or air, and the engine started up when cranked.

My point is that nowhere in the owner's manual does it say to loosen the banjo fitting to bleed the fuel line. I guess the warning is that procedures in the owner's manual are not necessarily adequate or the easiest. The manual say that the injector lines may have to be loosened and the engine cranked. My owner's manual also doesn't say that the tractor has to be running to adjust the steering play (with power steering), but the repair manual does.

 

[Bird]

TomG, I think several of us have experienced the problem you mentioned in regard to the quick couplers. My front end loader has the male connectors on the valve and the female connectors on the hoses (backwards from what I would consider the normal arrangement for quick couplers). And even though I do move the lever around to relieve all the pressure before disconnecting them, I've found that when the weather gets hot, there may be too much pressure in the hoses to hook them back up (all four of them once). But there's a much quicker and easier way to relieve the pressure than loosening fittings with a wrench, and that is to put a drift pin in the fitting and tap it with a hammer. Of course you want to be careful not to damage the pin in the female fitting and I wrap a rag around it to catch any fluid, but never lost more than a couple of drops. Just a tiny bit relieves the pressure.

And, yep, I learned to bleed that fuel line fitting just like you did on my B7100. Fortunately haven't had to do any bleeding on the B2710./w3tcompact/icons/smile.gif

Bird

 

[gordon]

To add on to Birds post I've done the same thing with a brass drift alittle softer metal and less chance of screwing something up. For those people with a heavy hammer hand. I've also used a screwdriver handle end as well as the screwdriver blade end too. Amazing the ideas you can come up with with only a few tools at hand when your in the woods./w3tcompact/icons/smile.gif
Gordon

 

[MChalkley]

And if it's the male end of a hose going to the implement that's got too much pressure on it, just wrap a rag around the tip and whack it head-on against something hard...

MarkC

 

[TomG]

For fuel filter changes, it would be handy if backing out a bleeding screw shut off the line from the filter bowl to the pump. Then fuel couldn't blackflow out of the line. Bleeders could be opened before removing the filter bowl, and there wouldn't be any chance of getting air past the filter bowl. I don't suppose they're designed like that though.

Maybe I learned my lesson and will never again disconnect a quick coupler without relieving the pressure first. However, lessons and me sometimes get lost. I didn't try Mark's solution of whacking the male end, but I think maybe a plastic hammer would have been quicker then loosening a fitting. I do know that pushing the male end (like a football lineman) didn't work.

 

[ERNIEB]

Since I use it alot I seldom take my loader off. It's been a while, but I think on my TC29D, there is a knob that controls the speed of the 3-point. By turning it all the way to the turtle position, it takes the pressure off the system, and the quick connects can be plugged and unplugged with the greatest of ease. Does that make sense?
ErnieB

 

[Bird]

Ernie, the problem I've seen really has little to do with the tractor. What has happened is that I've taken the loader off, in the shop (metal building), when the weather was comparatively cool, then try to put it back on in the heat of the afternoon (maybe on a different day) and the heat had caused just enough expansion of the hydraulic fluid in the loader cylinders and hoses that there was too much pressure to plug the connectors back together. I've seen a neighbor have the same problem with a hay baler and haybine left sitting out in the sun. So the trick is to relieve the pressure in the hoses on the implement.

Bird

 

[bpence]

Something you may try is to let the pressure out of the male connector when you disconnect the line. Just put a rag over the end, push against a piece of the equipment and let a bit of fluid flow out. You won't get much, but it will leave enough room for expansion and keep re-connect pressure down. My dad showed my that years ago when hooking up and unhooking the hydraulic lifts on plows and fold-up discs that generally sat for months at a time. Always seemed to work.

If you do have to relieve pressure when you reconnect, just do as Mark said and repeat the relief process. You shouldn't have hardly any pressure if you have to relieve at hook-up.

Bob Pence

 

[TomG]

The simple answer is that I'm not sure it makes sense, at least to my understanding. However, making sense isn't as important as getting something to work. I've had my hydraulics work in ways I can't explain, and I do have an attitude. Whatever works, I just keep doing it unless somebody tells me it's dangerous or hard on the equipment. The comments below may be useful for people who are just starting to get their minds around tractor hydraulics. I'm pretty sure everything said is fairly true, and I hope to be corrected if it isn't.

Most 3ph flow control valves affect the speed the 3ph lowers. The lift speed is not affected. The valve works by restricting return flow from the 3ph cylinder. When the valve is closed, the hitch won't lower but can raise to the limit of the cylinder travel. When the 3ph isn't actuated, oil flow in an open centred system goes through the 3ph remote control valve and returns to the reservoir. The flow control valve is not in series with oil flow in an open centred system.

I don't think turning off the flow control valve can be thought of as shutting off oil to the rest of the system. Also, when centred, open centred valves have the effect of isolating the pressure in cylinder lines from the rest of the system. At least with my system, I don't think the flow control valve would relieve pressures in the loader cylinder lines. However, I'd swear that once I couldn't lower the 3ph until I set the loader bucket down-can't explain that one either.

I'll also note that loaders can be plumbed into systems in various ways. My loader is hooked in series between the power steering priority valve and the 3ph. In this arrangement, the 3ph won't raise when any loader operation is active. Operating a loader valve closes the open centre, which closes off the oil input the 3ph. Hydraulic operations will not stop, but may be somewhat slower when the power steering is active. The power steering priority valve is a proportioning, rather than a diverting, valve. Power beyond systems are plumbed differently. I believe they use a three hose system, which contains a high pressure and a low pressure return line. However, I don't know enough about power beyond systems to comment further.

 

[ERNIEB]

Well, as I said I've only removed the loader a few times, three to be exact. The first two times hooking up the couplers was a real chore. Only managed after much straining, pushing, and spraying everthing within six feet with hydraulic oil(including myself). The third time I turned the flow control valve and I hooked them up with no problem.
After reading TomG's post, I pulled out my manual. No mention of the fcv helping in any way. Naturally, I had to see for myself. So out to the tractor I go. Short story, turning the fcv didn't help. Once again I was pushing, grunting and soaking rags with oil.
Puzzled, I went back to the loader manuel and read it again. Sure enough at the end of the section on removing the loader I read. "Engage the tractor brakes and stop the engine. Activate the control lever to relieve the pressure in both the bucket and lift circuits."
I guess I must have done this, without realizing it when I disconnected the third time and came to the false conclusion that the fcv was the reason. What is that they say? "when all else fails".
I'll have to try it again, but I think I'll wait a few days.
ErnieB