Independent PTO problems

[dtj1]

Hi. I am new to this forum and I need help. I have a 2008 Massey Ferguson 2625 four wheel drive tractor with independent PTO. When I turn the PTO on, the 3-point lift arms stops working. It has a new Hydraulic filter, and new oil. I am getting 2350 lbs. of pressure at 3-point lift arms test port. As soon as I turn the PTO on, the pressure falls to zero. I pulled the hydraulic lift cover off and I put the cap and stand pipe back on, I started the tractor to check to see if I had any leaks around the o rings, on the pipe but did not see any leaks, I had a good flow of oil came out of the stand pipe that feeds the 3-point lift arms and soon as I turned the PTO on, the oil from the stand pipe stopped and when I turned the PTO off the oil comes back through the stand pipe. Also the priority valve(part #2749A00401) has a open hole with a t stamped on it. I am wondering if a plug or something goes in that open hole. I nor anyone else cannot find any pictures of the priority valve to see if anything is missing. I've talked to several Massey dealerships and a service rep and they all told me they have never heard of this before. Does anyone have any ideas?

 

[Dave M7040]

Does your tractor have a loader, a loader with third function valve, or other hydraulic features like top and tilt.
Have you modified it or added to it or is is as stock as when it left the factory?
Dave M7040

 

[dtj1]

Yes it has a loader, It is stock as when it left the factory, and I have not added anything. Priority valve 2 with green sharpie is pointing to hole, that I am wondering if something is supposed to be in.

Thanks

 

[TractorTech]

Welcome to TBN!
Was it working, then stopped? Does oil come out of that hole in the priority valve?

 

[dtj1]

Welcome to TBN!
Was it working, then stopped? Does oil come out of that hole in the priority valve?

It had been working but I haven't used bush hog for about a month and when I went to use the bushhog this time that is when I had the problem. I do have a very small amount of oil come out of the hole from the priority valve when the PTO is engaged.

 

[rScotty]

Do you have the shop manual? It should show the hydraulic diagram for te 3pt and PTO.
With that, you should be able to identify which components might be diverting the flow. It will certainly show that diverter valve and that will tell you if the plug is missing. Some manuals list typical pressures at test points. If it isn't in the shop manual, ask the dealer.

So far it sounds like a stock system that worked fine for years and suddenly stopped working. Is that true?
If so, then something must have happened to divert the flow. The first thing any mechanci would want to know is what the possibilities are. The possibly missing plug is one; another might be a leaky PTO motor, or a 3pt relief valve that is stuck open.
The hydraulic diagram in the shop manual will show both of those possibilities and more. Most manuals also list the pressures at a test point or two to help diagnosis.

Here is the type of hydraulic diagram I'm talking about. Most dealer shops have these flow diagrams. They save a lot of time. These are from Yanmar showing a PTO with a manually-driven PT, but most of the 3pts are similar even if the PTO drive is not.
luck,
rScotty

 

[dtj1]

Yes it was working and then the next time I went to use it, the problem started and it is a stock system. I do have a shop manual from a Massey Dealer that went out of business, it's not very good on the PTO diagram and trouble shooting, but I drew in the missing parts (See Attachment). The pressures are good but I don't have a flow meter to check the flow. I was told to pull the lift cover off and start the tractor, if I am losing that much pressure, then I should see it, but nothing stood out to me and that's when I seen the hole in the priority valve and was asking about it. I have now drained the hydraulic oil and pulled the filter, to look for a plug or anything in the sump. I haven't found anything yet. I have a camera scope ordered. What the Massey Dealer told me the problem I am having does not make sense, because these are separate systems. The lift arm has its on pump, so does the PTO and the front end loader. The only thing they share is the suction filter. One should not affect the other, so the PTO is robbing all the fluid. So I am thinking I may have to invest in a flow meter. The bad thing is the priority valve and solenoid/flow control valve is non-serviceable and are not cheap, so I am trying to make a calculated guess.

 

[rScotty]

Yes it was working and then the next time I went to use it, the problem started and it is a stock system. I do have a shop manual from a Massey Dealer that went out of business, it's not very good on the PTO diagram and trouble shooting, but I drew in the missing parts (See Attachment). The pressures are good but I don't have a flow meter to check the flow. I was told to pull the lift cover off and start the tractor, if I am losing that much pressure, then I should see it, but nothing stood out to me and that's when I seen the hole in the priority valve and was asking about it. I have now drained the hydraulic oil and pulled the filter, to look for a plug or anything in the sump. I haven't found anything yet. I have a camera scope ordered. What the Massey Dealer told me the problem I am having does not make sense, because these are separate systems. The lift arm has its on pump, so does the PTO and the front end loader. The only thing they share is the suction filter. One should not affect the other, so the PTO is robbing all the fluid. So I am thinking I may have to invest in a flow meter. The bad thing is the priority valve and solenoid/flow control valve is non-serviceable and are not cheap, so I am trying to make a calculated guess.

Well, at least you do have a hydraulic diagram. That system is just enough different from a standard one to make a diagram a real help. Your hand drawn in PTO part make perfect sense, but the fact that they were not there originally makes me wonder if the (Independent)PTO was an option or afterthought. Do you know?

As you have drawn it, what you are calling the "priority valve" - not shown originally - has an input from the IPTO pump and an output to the solenoid flow switch. But I am puzzled why you are calling it a priority valve? A priority valve divides an input flow into two outputs. So if that is a priority valve, it should have an input and at least two outputs. Where is the other output?
Is the other output the missing plug?? And if so, is the missing plug in fact a relief valve? Or the outlet from one? If so is there a relief valve inside that aluminum valve block? In that case, the priority would be IPTO vs RELIEF and that would make sense. One would expect a relief valve somewhere in the IPTO system in case the PTO is stalled. Otherwise a stalled PTO would blow up the pump and maybe break the shaft.

Then we go over to the soleoid flow control (on/off) and I see that you have drawn in two return lines. Why are there two? Any idea?

Flow meters are very expensive but wonderful tools to have. I don't know of a small one for measuring flow in home shops for compact tractors. Even large dealers there days are unlikely to have a flow meter, although diagnosing hydraulics without one is a lot like doing electricals without a VOM.

Don't let me talk you out of a flow meter, but also consider buying or making a hydraulic pressure test kit (Amazon has them), and using that meter to plug the hole in the "priority valve". If so you might want to incorporate a relief valve in that test line just in case. It might show no pressure unless the IPTO is turned on and then stalled, and I would not recommend stalling the IPTO as a test even if you could....because it might cause major damage... Probably would.

rScotty

 

[Dman1981]

Did you clean sump screen just because they look clean is not always true

 

[dtj1]

Did you clean sump screen just because they look clean is not always true

This one does not have a screen, it has a filter and it is a new filter.

 

[dtj1]

Well, at least you do have a hydraulic diagram. That system is just enough different from a standard one to make a diagram a real help. Your hand drawn in PTO part make perfect sense, but the fact that they were not there originally makes me wonder if the (Independent)PTO was an option or afterthought. Do you know?

As you have drawn it, what you are calling the "priority valve" - not shown originally - has an input from the IPTO pump and an output to the solenoid flow switch. But I am puzzled why you are calling it a priority valve? A priority valve divides an input flow into two outputs. So if that is a priority valve, it should have an input and at least two outputs. Where is the other output?
Is the other output the missing plug?? And if so, is the missing plug in fact a relief valve? Or the outlet from one? If so is there a relief valve inside that aluminum valve block? In that case, the priority would be IPTO vs RELIEF and that would make sense. One would expect a relief valve somewhere in the IPTO system in case the PTO is stalled. Otherwise a stalled PTO would blow up the pump and maybe break the shaft.

Then we go over to the soleoid flow control (on/off) and I see that you have drawn in two return lines. Why are there two? Any idea?

Flow meters are very expensive but wonderful tools to have. I don't know of a small one for measuring flow in home shops for compact tractors. Even large dealers there days are unlikely to have a flow meter, although diagnosing hydraulics without one is a lot like doing electricals without a VOM.

Don't let me talk you out of a flow meter, but also consider buying or making a hydraulic pressure test kit (Amazon has them), and using that meter to plug the hole in the "priority valve". If so you might want to incorporate a relief valve in that test line just in case. It might show no pressure unless the IPTO is turned on and then stalled, and I would not recommend stalling the IPTO as a test even if you could....because it might cause major damage... Probably would.

rScotty

I am not sure of the options Massey offered on this model, maybe that is why the diagram is not complete, because of other options for it. I bought the tractor used in 2013 with 800 hours on it. I now have 1254 hours on it and have not had any problems with it until now. It is a factory stock tractor because I can find all the parts in my Massey parts book. I called it a priority valve because on the valve it self there is a tag on it that says priority valve. In the last picture I sent, you can't see the word priority because of the line and in the parts book it is listed as priority valve. The diagram I drew on, I was standing at the tractor and followed the lines and filled in where they went. The priority valve has one input line and one output line and the hole I been talking about. I don't know why the solenoid valve has two return lines. All my pressures are good. The only test left, that I haven't done is the flow test. The priority valve is $700 and solenoid valve is $1000 and only available through Massey and before I spent money guessing I was just trying to get some information. I did see a flow meter I could purchase for around $500.

 

[oldnslo]

Dtj
Per the schematic you posted this tractor has two separate pumps, P1 for PTO and the another for ferguson lift. Is Ferguson lift the 3 point? Also shows P2 for aux hydraulics. If that is correct the PTO should have no influence on the 3 point since only common point appears to be suction or pump inlets.

Is it possible the PTO is fed by the same pump that feeds the 3 point? Some systems have a pressure reducing valve or an orifice supplying PTO from main circuit.

 

[Dman1981]

There is a screen on that pump is a three hole plate on bottom of differential the Pto pump runs of a gear on the three point pump

 

[dtj1]

Dtj
Per the schematic you posted this tractor has two separate pumps, P1 for PTO and the another for ferguson lift. Is Ferguson lift the 3 point? Also shows P2 for aux hydraulics. If that is correct the PTO should have no influence on the 3 point since only common point appears to be suction or pump inlets.

Is it possible the PTO is fed by the same pump that feeds the 3 point? Some systems have a pressure reducing valve or an orifice supplying PTO from main circuit.

Yes, No. 10 on the schematic is the one that is for the 3 point lift in this picture, the one with the stand pipe attached on the right of the case, P1 is for my PTO, it is the smaller goldish color steel line on the left side with the banjo fitting on the pump to the priority valve, the block on the left side with the red tag. P2 is for the front end loader, it is the biggest goldish color steel line, it comes from the pump, it is the one in the center and goes out the left side above the priority valve that goes to the joy stick. The only thing they share is the suction filter. That is what is getting everyone that I have talked to from Massey. The only thing it could possibly be is that on the picture the left front, the P1-P2 pump (I was told that it is actually called axillary pump) is robbing the fluid from the lift pump for the 3 point lift but my loader does not effect the 3 point lift, only my PTO.

 

[dtj1]

There is a screen on that pump is a three hole plate on bottom of differential the Pto pump runs of a gear on the three point pump

No. 39 in the attachment, I called it a filter. It is supposed to be reusable but I just replace it with a new one.

 

[Dman1981]

They do run off same sump a little tube form Pto pump to suction side
Of three point pump it is a cleanable screen no need to change it
I would still clean it

 

[Dman1981]

I have seen screens that look ok but not have also had em when you rev them up would stop working also and implement drop create a vacuum from not enough oil

 

[oldnslo]

DTJ,
Doe this problem only happen when you try to operate the PTO solenoid and does it stop as soon as you de-energize the PTO solenoid? If yes then I would look at the solenoid valve to confirm that it is shifting fully and not allowing oil to by-pass and escape elsewhere. Since no known schematic it is hard to determine where the oil is going but that would seem to be the common item in failure vs working system.

 

[dtj1]

Update: After more testing I have now tracked it down to the lift pump. Now I
m focused on the lift pump trying to figure it out, what could be wrong with it, while the tractor was running, I started turning the PTO on and off, while watching it. I now see what is happening. When I turn the PTO on the PTO clutch pack or the movement of the oil is pushing the pump control valve lever through the neutral position, just enough to stop the lift from raising, after taking my finger and pushing the lever forward and letting it pop back a few times, it seems to be working. Now it still moves when I turn the PTO on and off but it does not effect the flow of the fluid, out of the stand pipe, like before. Has anyone seen this before? Could it be a weak or broke spring or O-ring in the control valve?
In the attached video, on the right side of the main shaft, you can see the pump control valve lever moving back in forth when I turn the PTO on and off.

Thanks.

 

[Dman1981]

The screen is plugged