M7040 3 Point slow lifting

[TheOldHokie]

Did you put a tee in place of that loop and then operate the three point to test it?

If you just removed a line and pressure tested the pump output without a tee.
I can tell you without a doubt the pump is shot!

If thats the case the pumps on both tractors are shot.

Dan

 

[eserv]

Did you put a tee in place of that loop and then operate the three point to test it?

If you just removed a line and pressure tested the pump output without a tee.
I can tell you without a doubt the pump is shot!

If it wasn't it likely is now!

 

[North Idaho Wolfman]

Still need a definitive answer on post #14:

M7040 3 Point slow lifting

I have an M7040 that you must increase the RPMs to lift heavier items. It used to lift them, no problem and now its extremely slow even when increasing RPMs. Back story. The tractor went into the lake last year. I changed filters and fluids three times to flush the system. Then, after the...

www.orangetractortalks.com

 

[lugbolt]

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.

 

[Mikec575]

If thats the case the pumps on both tractors are shot.

Dan

No I did not connect to the loop. I connected to the rear remote.
Do you know where the pressure relief valve is on the 3 point

 

[Mikec575]

Let me be real clear:
My picture is the Block your picture is bracket and pipe:
So which exactly do you have?

Block:

View attachment 128986

Bracket and pipe:

View attachment 128988

My apologizes. I am doing this on my phone and now that I was able to zoom I see what you are saying. I have the bracket and pipe not the block.

 

[TheOldHokie]

No I did not connect to the loop. I connected to the rear remote.
Do you know where the pressure relief valve is on the 3 point

I believe its part of the valve - not easily accessed.

I would suggest you do a pressure test at the lift cylinders. Remove both base end hoses and plug one of them. Attach your gauge to the other, start tje tractor, and move the 3pt lever to the raise position. That will tell you what pressure the cylinders are seeing. If its in the proper range it would lead me to suspect the cylinders are leaking.

Dan

 

[Mikec575]

I believe its part of the valve - not easily accessed.

I would suggest you do a pressure test at the lift cylinders. Remove both base end hoses and plug one of them. Attach your gauge to the other, start tje tractor, and move the 3pt lever to the raise position. That will tell you what pressure the cylinders are seeing. If its in the proper range it would lead me to suspect the cylinders are leaking.

Dan

Ok I can do that. Question. Since I have the pipes and not the blocks, I have a flow/pressure tester. Should I take the loop pipe out and just hook up to that and confirm pump pressure also?

 

[Mikec575]

Still need a definitive answer on post #14:

M7040 3 Point slow lifting

I have an M7040 that you must increase the RPMs to lift heavier items. It used to lift them, no problem and now its extremely slow even when increasing RPMs. Back story. The tractor went into the lake last year. I changed filters and fluids three times to flush the system. Then, after the...

www.orangetractortalks.com

I have the pipes and NOT the block sorry

 

[North Idaho Wolfman]

I have the pipes and NOT the block sorry

Thanks, just wanted to make sure we were talking about the same things.

 

[North Idaho Wolfman]

I believe its part of the valve - not easily accessed.

I would suggest you do a pressure test at the lift cylinders. Remove both base end hoses and plug one of them. Attach your gauge to the other, start tje tractor, and move the 3pt lever to the raise position. That will tell you what pressure the cylinders are seeing. If its in the proper range it would lead me to suspect the cylinders are leaking.

Dan

Actually on that model they are very accessible:
I personally would pull all three and inspect.

And you can tell if the cylinders are leaking by pulling off the vent hose, quick and simple leak check.

 

[TheOldHokie]

Actually on that model they are very accessible:
I personally would pull all three and inspect.

And you can tell if the cylinders are leaking by pulling off the vent hose, quick and simple leak check.

View attachment 129092

Thanks for the correctuon - Iwas working feom memory and thought those were in the valve for some reason.

 

[TheOldHokie]

Ok I can do that. Question. Since I have the pipes and not the blocks, I have a flow/pressure tester. Should I take the loop pipe out and just hook up to that and confirm pump pressure also?

If you have the proper setup by all means test pump.outlet pressure. Sounds like you know the drill so dont take offense if this is obvious to you. Its not for many people.

You hook the tester to the pump outlet pipe and run the return back into the hydraulic sump filler.

Then FULLY open the loading valve on the tester and start thr engine. With the engine running @ roughly 3/4 speed slowly start to close the loading valve while watching pressure. Pressure should start to rise and hit the target (2500+ PSI) before the loading valve is fully closed. There is no relief valve in the system when hooked up like that and you do not want to deadhead the pump by completely closing that valve.

That test will go a long way towards knowing where to look for the problem

Dan

 

[Mikec575]

If it wasn't it likely is now!

I teste

Actually on that model they are very accessible:
I personally would pull all three and inspect.

And you can tell if the cylinders are leaking by pulling off the vent hose, quick and simple leak check.

View attachment 129092

So dumb question #10 is the relief valve, #50 is a safety valve per the WSM is that a backup to the relief valve incase it doesn’t relief? What is #90s purpose ?

 

[Mikec575]

If you have the proper setup by all means test pump.outlet pressure. Sounds like you know the drill so dont take offense if this is obvious to you. Its not for many people.

You hook the tester to the pump outlet pipe and run the return back into the hydraulic sump filler.

Then FULLY open the loading valve on the tester and start thr engine. With the engine running @ roughly 3/4 speed slowly start to close the loading valve while watching pressure. Pressure should start to rise and hit the target (2500+ PSI) before the loading valve is fully closed. There is no relief valve in the system when hooked up like that and you do not want to deadhead the pump by completely closing that valve.

That test will go a long way towards knowing where to look for the problem

Dan

No offense taken!! Thank you!! I knew not to close the valve all the way, but always appreciate the reminder and the instructions to backup my thoughts. I am not a full time mechanic, I am a fireman, so I am always willing to listen. I have gotten A LOT of good information from A lot of good people on here.

 

[TheOldHokie]

I teste

So dumb question #10 is the relief valve, #50 is a safety valve per the WSM is that a backup to the relief valve incase it doesn’t relief? What is #90s purpose ?

The only dumb question is the one not asked.

Thr relief valve is on the pump side of the lift control vslve and sets thr upper limit on the incoming pressure from the pump. Once the lift reaches the desired hrigjt and the control valve closes it is no longer in the lift circuit.

The safety valve is on the cylinder side of the lift control valve and is set a few 100 PSI or so higher than the pump relief. When the lift control valve is closed the safety valve is holding the pressure of the raised load. When you start moving around with a raised load on the lift bumps and uneven terrain causes the load to bounce genersting pressure spikes in the lift cylinder. The purpose of the safety valve is to open and cushion those spikes preventing hydraulic overpressure that could damage the lift components.

That cushioning might cause the lift height to drop slightly. If/when it does the position control feedback senses it and the lift control valve is automagicslly opened to raise it back to the set height

Clear as mud?

Dan

 

[Mikec575]

The only dumb question is the one not asked.

Thr relief valve is on the pump side of the lift control vslve and sets thr upper limit on the incoming pressure from the pump. Once the lift reaches the desired hrigjt and the control valve closes it is no longer in the lift circuit.

The safety valve is on the cylinder side of the lift control valve and is set a few 100 PSI or so higher than the pump relief. When the lift control valve is closed the safety valve is holding the pressure of the raised load. When you start moving around with a raised load on the lift bumps and uneven terrain causes the load to bounce genersting pressure spikes in the lift cylinder. The purpose of the safety valve is to open and cushion those spikes preventing hydraulic overpressure that could damage the lift components.

That cushioning might cause the lift height to drop slightly. If/when it does the position control feedback senses it and the lift control valve is automagicslly opened to raise it back to the set height

Clear as mud?

Dan

Clear as mud!!! Great explanation. Makes perfect sense. Thank you!!

 

[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.

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

 

[Russell King]

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

PVC = poly vinyl chloride (usually referring to pipe)

PCV = position control valve (in most cases referring to tractor)

probably spellcheck changed it but really made me stop and think about what was being discussed!

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

 

[Mikec575]

PVC = poly vinyl chloride (usually referring to pipe)

PCV = position control valve (in most cases referring to tractor)

probably spellcheck changed it but really made me stop and think about what was being discussed!

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

That’s my bad, I know it typed it write because I was thinking the same thing and wanted to make sure I got it right but spell check obviously got me