M7040 3 Point slow lifting

[TheOldHokie]

Is #10 the PVC you are speaking of? meaning the rock cover has to come off to access?

Have you checked pressure at the cylinders yet? I would not take anything apart until I confirmed the pressure from the tractor was low.

Dan

Dan

 

[Mikec575]

Have you checked pressure at the cylinders yet? I would not take anything apart until I confirmed the pressure from the tractor was low.

Dan

Dan

Mr. Dan, Yes I have and at idle it’s less than 200 at the cylinder. I have made some bone head moves since Friday. Prior to me making the original post I had already ordered and paid to have a pump overnighted because I needed the tractor for the weekend. The new pump didn’t change a thing, secondly I have another tractor that is working perfectly and I switched the relief valves and the tractor with issues still has issues and the other one works fine.
The PCV is looking to be my last resort??

 

[lugbolt]

Is #10 the PVC you are speaking of? meaning the rock cover has to come off to access?

yeah. Lift control valve as Dan called it, position control valve, all the same thing.

 

[Tx Jim]

I have made some bone head moves since Friday. Prior to me making the original post I had already ordered and paid to have a pump overnighted because I needed the tractor for the weekend. The new pump didn’t change a thing,

Over the many yrs I been associated with repairing tractors I've read of many hyd pumps being replaced without good hyd diagnostic procedures being performed only to determine as you did that the replaced hyd pump was not the problem. I also agree some hyd diagnostic procedures can be difficult to perform.

 

[Russell King]

And yes the PCV is under the cover. There is a recent posting that shows this but I can’t find it

Found the thread with the top cove removed showing th position control valve

Start looking at post 77 for pictures and links to videos

L2350DT Hydraulic Problem 3-PT Shakes

Everything as normal except your comment on the lowering speed valve. You start by saying valve is open and then you say it won't lower unless you open it. That is contradictory. Was the test run with the lowering speed valve open or closed? It should be run with the valve open. Need a much...

www.orangetractortalks.com

 

[Mikec575]

Found the thread with the top cove removed showing th position control valve

Start looking at post 77 for pictures and links to videos

L2350DT Hydraulic Problem 3-PT Shakes

Everything as normal except your comment on the lowering speed valve. You start by saying valve is open and then you say it won't lower unless you open it. That is contradictory. Was the test run with the lowering speed valve open or closed? It should be run with the valve open. Need a much...

www.orangetractortalks.com

Awesome thank you

 

[Mikec575]

Awesome thank you

So I finally found the problem. The draft linkage was beginning to freeze up. I disconnected the linkage (shown in picture) and noticed it was a little hard to move back and forth. I exercised it and now it has 1500 psi at the remote at idle.

 

[Mikec575]

M

Have you checked pressure at the cylinders yet? I would not take anything apart until I confirmed the pressure from the tractor was low.

Dan

Dan

Mr Dan just wanted to let you know I was able to fix the issue and wasn’t sure if you saw the post. I disconnected the draft linkage and exercised the rod which seemed like it was trying to freeze up.

 

[Mikec575]

i've done quite a few of those M-40's with bad/leaking (internally) position control valves. On most of the cabin models you have to lift the cab a little bit to get the top cover off to get access to the PCV. Then you can take the valve off, take it apart, free up the sticking valve(s) and reassemble. Make sure you have a service manual handy as there are a couple of adjustments that need to be made.

but before deeming it bad, you really should test the hydraulic pump-the correct way. Pressure AND flow. Need to make sure the pump is not damaged and the rest of the system feeding the pump isn't restricting flow.

the valves can get sticky in the pcv which causes an internal leak, which reduces pressure available to the rockshaft cylinders Raising RPM increases hydraulic fluid flow enough to make a little more pressure. Remember, pressure is a sum of restrictions in the system. Sometimes you can get them apart to repair, other times not. On the majority of the ones I did, I found that they were using tractor supply company "Kubota compatible" hydraulic fluid. I can't blame them, it's cheaper, but there was question as to whether the hydraulic fluid might have contributed to the valve sticking. I couldn't answer that question other than I've seen a few of them with the same issue and they all used cheap fluid.

So do you think the draft rod is freezing up were it goes into the rock cover or would it be in the valve, either way the cover has to come off correct? It’s working now but with me just exercising that rod a couple times I am sure it’s not long before it stops working again.

 

[TheOldHokie]

M

Mr Dan just wanted to let you know I was able to fix the issue and wasn’t sure if you saw the post. I disconnected the draft linkage and exercised the rod which seemed like it was trying to freeze up.

Thats interesting but I fail to see how that would affect pressure at a remote. Presumably the remotes are ahead of thd 3pt valve. A WSM would be helpful.

PS> 1500 PSI is still way lower than I would think normal.

Dan

 

[Mikec575]

Thats interesting but I fail to see how that would affect pressure at a remote. Presumably the remotes are ahead of thd 3pt valve. A WSM would be helpful.

PS> 1500 PSI is still way lower than I would think normal.

Dan

The WSM calls for 2632 -2770psi at 2600 and it’s just over 2600 at 2600 RPMs. I have a hard enough time with draft in general but I guess if it’s not closing all the way it was allowing pressure to bypass???

 

[TheOldHokie]

The WSM calls for 2632 -2770psi at 2600 and it’s just over 2600 at 2600 RPMs. I have a hard enough time with draft in general but I guess if it’s not closing all the way it was allowing pressure to bypass???

So you are in fact getting full pressure at the remotes.

Draft control and position control are different fumctions. Are you talking about the lever thst switches between the two? You need to be in position control to get the behavior you want.

Dan

 

[Mikec575]

So you are in fact getting full pressure at the remotes.

Draft control and position control are different fumctions. Are you talking about the lever thst switches between the two? You need to be in position control to get the behavior you want.

Dan

The WSM is calling the rod the draft feedback rod.
It’s #3 in the attached photo is the one I disconnected and exercised.

 

[TheOldHokie]

The WSM is calling the rod the draft feedback rod.
It’s #3 in the attached photo is the one I disconnected and exercised.

I can see how draft control might be causing your 3pt lift problem. I cannot see how it would affect pressure at the remote. Your pressure test indicates you are getting full system pressure delivered to the 3pt control valve.

Dan

 

[Mikec575]

I can see how draft control might be causing your 3pt lift problem. I cannot see how it would affect pressure at the remote. Your pressure test indicates you are getting full system pressure delivered to the 3pt control valve.

Dan

Understood. So a couple factors, human (lol), secondly I went to Kubota and bought new fittings for the remote, lastly I took the relief valve out for another visual inspection and backed it off a turn, tightened it two turns. So unfortunately to many variables to nail it down to one, but the draft controls “probably” had nothing to do with remote pressure.