trouble connecting skid steer quick disconnects

[CurlyDave]

This thread http://www.tractorbynet.com/forums/hydraulics/131755-help-my-stucchi-disconnect.html addresses the problem.

IMHO the very best solution is a few spare connectors, with the rear (pipe thread) end loosely capped with a plastic fitting, which are mated with the implement lines as soon as the implement is disconnected. This prevents the pressure build up from happening in the first place.

The caulking gun approach discussed works pretty well also and is inexpensive to try.

 

[scuvnut]

That is the point I was trying to make, there is nothing to push against. Most tractors do not use flat face QD's. You have to release fluid some other way. Put a tee in-line on the hose from the attachment, and release the fluid when you have to. It will only cause problems when it is very hot, causing the fluid to expand. Should not have this trouble in the winter time. You could perhaps make a tool to push in on the flat face of the QD, a special plier type tool that would hook on the bottom of the QD, and push in on the flat face of the QD.

Ahhhh....I see said the blind man. Thanks for the little extra explanation. Apparently, I was being as dense as the hydraulic fluid!

 

[scuvnut]

This thread http://www.tractorbynet.com/forums/hydraulics/131755-help-my-stucchi-disconnect.html addresses the problem.

IMHO the very best solution is a few spare connectors, with the rear (pipe thread) end loosely capped with a plastic fitting, which are mated with the implement lines as soon as the implement is disconnected. This prevents the pressure build up from happening in the first place.

The caulking gun approach discussed works pretty well also and is inexpensive to try.

CurlyDave - thanks for your input and I hope you don't mind if I explore this a bit further to assist in my understanding. I buy my QD from discounthydraulichose and an extra set would just over $60, but if it would solve the issue, then its worth it.

However, for example, if I"m using the 4 in 1 bucket and go to change it, you are saying that as soon as I disconnect it to connect this spare set. Won't that be too late? Seemes that as soon as I disconnect is, the thermal expansion is already there and that connecting the extra set would be difficult and thus put me in the same circumstance that I am in.

Could you also give me a little insight on the QD male and female coupling itself. When you put them together, do these coupling both compress and open or does the male open the female or vice versa? Maybe I'm overthinking this, but the problem is always with the male connector from the implement going into the female coupling on my tractor.

In the thread you pointed me to, you stated "you can bleed the pressure on the tractor side to nothing". I assume this is accomplished by simply moving the lever for that remote on/off and lowering the 3 pt hitch, when the tractor is off, right?

I'm probably being overly analytic here, but I'm trying to fully understand this problem. Thanks

 

[J_J]

scuvnut ,

Let me try answering the QD thing. Some tractors have two male QD fittings off the valve, and the attachments have two female QD fittings. If this is the case, then make up a set of male QD fittings with about a four ft hose, and plug into the QD's for the attachments, and you are ready for the next time. The air in the adapter hose will keep the fittings from locking up caused by hyd fluid expanding. If the attachments have a male and a female, then make up a four ft hose with a male and a female QD on the ends, and plug into the attachment. This also keeps keep them clean.

The tee and cap or needle valve on the attachment hose will cost the least .

Both parts of the QD closed to prevent leaking.

 

[radman1]

I have also discovered it is best to unhook flat faced couplers when the hydraulic oil is hot. Then when everything has cooled, the oil in the hoses do not get the expansion from the hot surrounding air and the couplers reconnect easier. Also, many couplers are O-ring connectors. Just unscrew slightly and let a little oil out to releive the pressure. Then retighten. This won't work well for pipe thread fittings which will need a sealant before retightening.

 

[CurlyDave]

Here is a picture of the fittings I use. It is slightly blurry because I used a macro setting on the lens and got in really close to the fittings. The top of the hex flats is in focus, all the rest is slightly out.

You can see the plastic pipe plugs I used to close the back of the fittings. I did not say seal, because I don't want them to seal. There should be a very slight pressure leak here to relieve any pressure build up from thermal expansion. The only purpose of the plastic pipe plug is to keep dust, dirt and water out. I did not use thread sealant on the pipe plugs.

My tractor is set up with nominal 1/2" fittings, one male and one female.

Both the male and female internally seal when they are disconnected.

Thermal expansion is only a problem if the oil changes temperature between when you disconnect the implement from the tractor and when you try to connect the dummy fitting, which is why you should do it right away.

I normally carry the caulking gun I showed in the other thread on the tractor, and if there is any difficulty making up the connection with the dummy fitting, it is very easy to overcome with the caulking gun.

JJ:

I don't think a hydraulic hose between these fittings would be of any help. It would make a closed circuit and it would still be easy to build up pressure in the sun. What you really want is either a very slight leak, to prevent pressure from building up, or a tee and an extra valve as you advocated before.

 

[scuvnut]

CurlyDave

Thanks for the continued discussion on this.

I believe you are saying to put the extra set of QD onto the implement. However, I'm quite sure the problem is on the tractor side. The female on the tractor seems to be the problem. Or, are you saying to put that extra set on the tractor side?

In a prior post, you said "you can bleed the pressure on the tractor side to nothing". How?

Thanks!

 

[CurlyDave]

1. I put the extra set of disconnects on the implement.

In a prior post, you said "you can bleed the pressure on the tractor side to nothing". How?

2. To reduce hydraulic pressure on the tractor side to zero, turn the engine off, turn the "ignition" on, and actuate the control for the hydraulic circuit several times.

For instance, if I want to reduce the hydraulic pressure in my FEL circuit to zero, I shut down the engine, then turn the key on, and actuate the joystick both to raise & lower the FEL arms, and to curl and uncurl the bucket. These should be long, deliberate actuations. Lower the FEL to the ground and hold the joystick forward for at least a full second after it reaches the ground, then try to dump the bucket for a full second after it comes to rest on the ground, curl the bucket and then try to raise the bucket. Repeat. You have now bled off all pressure in the FEL circuit, but the rear remotes can still have pressure, so repeat the process for that circuit.

* * * * *

No matter which side of the circuit, the implement or the tractor, has residual pressure you will have difficulty making the connection. Both the male and female side of the skid steer style disconnects seal pressure, and both have a flat surface which must be depressed to make up the connection.

The difference is that you can bleed down the tractor, but you can not do this with the implement it its stock configuration.

It may well be worth the cost of a set of fittings just to be able to dissect them and see for yourself how they really work...

 

[scuvnut]

Excellent....I fully understand now. Appreciate your time. Ordering a set of right now.

Addendum: just ordered the extra set. Will report back as soon as I receive them and try this out.

 

[J_J]

Just thinking out loud here, but plugging the implement QD's into each other would satisfy the ability to release all pressure from the implement in order to connect them to the tractor. The trouble with the QD's is pressure pushing on the backside of the center nipples. When you are releasing them, you pull or push back the sleeve, and it seems like they should spring open. I was trying to remember a time when I could not release the QD's on my implements. If you do not connect them together, then you will have to push against tractor pressure. Also, would it not be logical to plug in the return line first, then the pressure line last. I am not sure, but is it standard, that the male QD is the pressure line off the tractor

Plugging into the tractor is the trouble, because you are trying to push against pressure. So if the tractor is bleed correctly at shut down, and the QD's on the implement were plugged into each other, would there still be a problem.