I think i broke something....

[BigCountry1689]

If I take out the spool, washers, spring, and pins and reassemble will that allow the valve to flow freely allowing me to test to see if it is infact the valve causing the pressure issue.

 

[Coyote machine]

If I take out the spool, washers, spring, and pins and reassemble will that allow the valve to flow freely allowing me to test to see if it is infact the valve causing the pressure issue.

For clarity, you said you had to replace a cylinder on your loader before you started working? As in you removed and replaced a hydraulic ram assembly to raise or curl your loader when in use? Why, did something break on this cylinder? Did this occur before you had any hydraulic leak present at the third function valve?

When you noticed the third function valve leaking you said you found a couple of screws/plugs loose? Were these what holds the valve assembly together?
You also found a o-ring damaged- inside the 3rd function valve? Where if not inside it?

When you disassemble the valve body you are looking for any particulate debris from assembly, or otherwise, that might be causing the valve to block flow to it's various ports. Try to disassemble somewhere you can track anything that might be stuck in the valve body, in one of it's ports, etc. Use clean shop towels, preferably paper, to reduce the chance of contaminating the valve while working on it, (HST systems are very unforgiving of any foreign particles, dirt, lint, etc.) Think surgically clean environment and you'll do fine.

When draining any fluid from your hydraulic tank, cleanliness is also of absolute importance, so be cautious when doing so.

Take it one step at a time- you'll find what the issue is by eliminating the 3rd function valve as being the culprit. Right now it sounds like the source of the malfunction, but let's better understand what you referred to regarding the loader cylinder replacement too - you could have several issues working against you right now.

 

[MinnesotaEric]

If I take out the spool, washers, spring, and pins and reassemble will that allow the valve to flow freely allowing me to test to see if it is infact the valve causing the pressure issue.

What Coyote machine shared is all true and my additional comments should be considered in the context of his remarks.

For clarity, the o-ring you replaced was on the third function valve we're now talking about, right?

Question: was the replacement o-ring an OEM o-ring or something out of a universal kit?

O-rings are not all manufactured equally and some are good for sealing one thing, but not another, if you follow me.

If I've understood things correctly, the problem began with the replacement of the o-ring.

Therefore, my conjecture is that the o-ring you put in has swelled and is binding on the valve and keeping the spool valve from centering in the valve body.

Theory. Your system has something akin to the following hydraulic diagram.

If you can imagine looking at the image above, fluid is always flowing from the pump ( P ) to the tank ( T ) which is drawn as the elongated "U" at the very bottom of the diagram. When you hit the ( A ) button, the electromagnet pulls the spool valve over to that side allowing fluid from the pump to flow through the ( A ) of the ram. When you release the ( A ) button, the valve centers again and fluid resumes flowing from the pump back to the tank. When you hit the ( B ) button, fluid from the pump flows through the ( B ) side of the valve body to the other side of the same ram that the ( A ) side of the spool valve feeds. When you release the ( B ) button, the valve centers again and fluid from the pump flows back to the tank.

So that is how this valve works. Since you have two rams, both ( A ) and ( B ) feed either side of two rams, but the idea remains the same for both.

Now imagine your problem and imagine if the spool valve, for whatever reason could not center in the valve body?

If the spool valve cannot center into the valve body due to excessive drag from a replacement o-ring, then we may give most of the flow ( P ) to the tank ( T ) from the pump but we may also keep a little fluid flowing to one side of the ram ( either A or B ) forcing the ram to try and operate.

Follow my thinking?

Anyway, the puzzling out of your problem above is why I'm thinking the o-ring you replaced is not to spec for the spool valve and you need to replace that same o-ring with a hydraulic fluid, heat-friendly o-ring made for your valve body and spool.

 

[BigCountry1689]

Alright it has been a busy morning, I will attach photos as I go along.

First thing I decided to try the instruction for bleeding the HST. This did help some it allowed me to now be able to operate steering,loader, and 3pt with out any rpm loss like before. But I still have little FWD, REV and third function. Attached are the photos of the 3rd function along with the plugs I was talking about. The first picture is of the plugs that were leaking the second is of the front plugs (there are 2 on each side). I followed all percautions prescibed. Stole the wifes beach towel, and other things that I didnt think she would miss, I also got her new dish gloves. I used the leaf blower and blew off all debris, and further used brake cleaner to get rid of any residues. I then preceeded to take apart the valve, it was pretty much as the video showed. The spool was easy to push out through the right side, but would not come out on the left side. I saw no debris or shavings in the oil and I collected everything that dripped out in a piece of tupperware. After checking all that I reassembled and checked for leaks, nothing was visible.

 

[BigCountry1689]

Here are the pics I could not insert inline.

 

[BigCountry1689]

Next spoke to the dealer he wanted me to check the HST vemt line first. Did that and it was clear but to be sure i removed it and blew it out with the air hose.

Here is the HST level currently with engine cold and all cylinders down.


Someone had asked about the cylinder, it was the left side cylinder on the grapple that needed replacing.



I also have called EA reference the valve to get there insight (Helpful as always). I have sent them pics and they are contacting WR Long for tech support.

I will contact the dealer again and see what he thinks next. I was thinking about draining all HST oil and starting over with that as well to see if that helped any. I dont generally like mixing oil when avoidable.

 

[Coyote machine]

So far you'd found nothing that would indicate cause/effect. But you have verified that the 3rd function valve has no debris caught internally.
Questions asked still need to be answered.
Is the O-ring you replaced from inside the 3rd function valve and exact match to what was removed, or something you matched up in a random store selection?

I asked about the cylinder you mentioned having replaced. I want to know why you replaced the cylinder, and when. Also, did this cylinder replacement take place BEFORE you found the valve leaking?

I would NOT change the hydraulic fluid now. If and when we find the cause/effect and everything is back to working properly, then you might change it - but I don't see any value to doing so now.

In case you didn't mention it earlier- how many hours on the machine, and how many of those has the 3rd function valve and grapple been in place?

Your dipstick fluid level looks to be above the full mark? If it is, get it to just at full, (tractor on level surface), engine off. Too full can overpressure the seals and cause other potential issues.

Can you detach the grapple from the 3rd function valve by uncoupling the QDs? If so do it and see, after getting the fluid level on the mark, if running the tractor around the yard brings about any changes, positive or otherwise.
Look for any continued foaming, and similar indicators. Try operating all the other functions, loader, all circuits, 3ph, etc.

Report back results and answers to above questions.

Thanks,

CM

 

[BigCountry1689]

Coyote Machine;

Sorry for sporadic answering of questions, lots of questions asked and I missed some.

#1- If you look at post #35 picture you will see the plug I referenced that was leaking. just under the flange is where the O-ring sits. the actual threaded part is much smaller that the head would show and it sits external of the valve body. I checked the plugs on the opposing side and they are all the way tightened down. I tried to take a picture of the hole with the plug removed but the camera died on me. At any rate the plugs have no tip to them and just lead to an open cavity I see no restricting ability or any flow control function just a hole. I talked to the dealer and he feels like they might be to release air/pressure after install??? I contacted EA today and they are working with WR Long to provide more answers on the valve assembly, apparently they source a multitude of valves and have to research the particular one I have.

#2- Post #36 on the last picture, I have a picture of the cylinder that was replaced. I had replaced that cylinder on the left side of the grapple first thing on the morning all issues had started. I followed the directions provided which were essentially plug and play. The cylinder was replaced because it developed a seal leak around the piston shaft ( just a weeping leak but it was under warranty so I replaced it). The plug was the only thing that was leaking and it appeared to me that it probably just was not tightened fully at assembly and had worked loose, all others were tightened all the way down and this one was loose (finger loose).

Question: With the leaking and then me removing the plug completely and letting all that air into the system is it probable that the trapped air is causing the problem (Again I don't know hydraulics so I am not sure how that air escapes)? I did study Eric's diagram and instructions on hydraulic flow but wasn't sure if that air becomes trapped. The dealer seems to think that it could be and that the positive pressure flow from the hydraulic fluid is pushing on the trapped air and then when the switch on the 3rd function is deactivated the pressure reduces causing the push back of the grapple arm.

#3-The tractor currently has 27.8 hours.

#4- the dipstick actually has 2 notches on it and the fluid is sitting just above the bottom notch indicating that it is on the low side of normal.

#5- The grapple actually has been disconnected since this started, that was the first thing I did, the 3rd function has two QD's that remove the hoses from the valve.

I spoke to the dealer before work this afternoon and he consulted with Kioti today, there feeling as of right now is that this might have started as 1 issue and become 2 separate problems now that have to be looked at. (1) with the HST and (1) with the diverter. Because he installed the diverter they are responsible for it thankfully. Though I do have a very good dealer so I wasn't concerned. The wife being how she is worked out something in the purchase contract that if there is a warranty issue that the dealer comes and gets the tractor and brings it home for $300 round trip, which saves me 3 hrs. one way of driving. I didn't even know until I told her that I had to take it to the dealer for repair. The dealer will be calling me in the A.M to tell me when he will be retrieving the tractor for repair as Kitoi wants to see what's wrong. They are concerned because of the fluid overheating and frothing that there might be a more serious issue that could get very costly. I will keep you all up to date as to the progress.

Thanks BC

 

[Coyote machine]

BC, Thanks for the detailed reply. It is hard to know if the air that may be trapped somewhere in the hydraulics is causing/was causing your other issues of poorly functioning hydraulically controlled items like your loader, etc. What you do know is there was an issue with a weeping grapple cylinder, then there is/was an issue with the 3rd function, (not diverter) valve. These malfunctions and fluid leaks lead to where things are now. How exactly is still somewhat unknown, BUT if your dealer is going to retrieve your tractor- all the better for the overall outcome.

Somewhere someone missed some seal and screw/plug QC when the grapple cylinder and 3rd function valves were assembled.
Regardless, give the dealer the details, (as you did above for us), and let them sort it out. Possibly print out a copy of what you just detailed for us, and give it to them for reference. Not all pages, just the specifics as to what happened when.

They'be be able to do the bleed sequence, make sure the fluid is not foaming, and replace the 3rd function valve, as needed.

Post back the results or any questions in the interim.:thumbsup:

 

[ritcheyvs]

Just commenting now. I couldn't understand what little screw could have worked lose but the photos in post 35 cleared that up. The actual valve is the cube that says APC on the side but all the hydraulic connections are all made through the metal block that is bolted to the actual valve. Apparently, the block was designed to accommodate a variety of connections from different directions and these "small screws" are just plugs to close the unused holes. I wonder why the spool would only exit one side of the valve body? Maybe this valve body was machined to only allow removal from one side, even though the valve in the video showed removal from either side? Or could there be debris or damage that prevented the spool from exiting the other side? The valve spools are designed to be balanced so they are not effected by different pressures on different ports, but trapped air can do funny things in hydraulic systems; so maybe that's a factor. Air would have gotten into the system both when the cylinder was replaced and when the screw plug was open. I usually cycle a new cylinder several times to purge any air, which worked fine, but I've never used a selector valve. This has been a very educational thread but probably less entertaining for the OP.