M7040 3 point weakens throughout the day

[Mikec575]

My M7040 3 point will pick up implements in the morning and after lunch I have to bring the RPM up to get it to lift the same weight it lifted before lunch at an idle.
any suggestions?
comparison- M7060 will lift the back of my gooseneck no problem and the M7040 barely lifts it when bringing the RPMs up.

 

[TheOldHokie]

My M7040 3 point will pick up implements in the morning and after lunch I have to bring the RPM up to get it to lift the same weight it lifted before lunch at an idle.
any suggestions?
comparison- M7060 will lift the back of my gooseneck no problem and the M7040 barely lifts it when bringing the RPMs up.

Something in your hydraulic system is bypassing oil when the oil warms up and thins out. The two main suspects are the 3pt lift cylinder and/or the hydraulic pump. Do you have a loader on the tractor?

Dan

 

[Mikec575]

My M7040 3 point will pick up implements in the morning and after lunch I have to bring the RPM up to get it to lift the same weight it lifted before lunch at an idle.
any suggestions?
comparison- M7060 will lift the back of my gooseneck no problem and the M7040 barely lifts it when bringing the RPMs up.

Something in your hydraulic system is bypassing oil when the oil warms up and thins out. The two main suspects are the 3pt lift cylinder and/or the hydraulic pump. Do you have a loader on the tractor?

Dan

No sir I do not have a loader on it

 

[TheOldHokie]

No sir I do not have a loader on it

I would suggest a couple simple tests. Conduct each test before the oil is warmed up and again after its warmed up and you are loosing lift.

1. Check for cylinder bypass. Remove the small return hoses on the lift cylinders and check for fluid when you raise a heavy load. Ideally there should be none.
2. Measure pump pressure. Plug a pressure gauge into your rear remote and operate the control lever to get a pressure reading. Factory specification is 2770 PSI.

 

[Mikec575]

I would suggest a couple simple tests. Conduct each test before the oil is warmed up and again after its warmed up and you are loosing lift.

1. Check for cylinder bypass. Remove the small return hoses on the lift cylinders and check for fluid when you raise a heavy load. Ideally there should be none.
2. Measure pump pressure. Plug a pressure gauge into your rear remote and operate the control lever to get a pressure reading. Factory specification is 2770 PSI.

How can I go about seeing if it is bypassing in the steering system?
I am only getting about 1300 psi at the rear remote.
I took the hoses off the rear lift cylinders and there is no fluid coming out of the cylinders.

 

[TheOldHokie]

How can I go about seeing if it is bypassing in the steering system?
I am only getting about 1300 psi at the rear remote.
I took the hoses off the rear lift cylinders and there is no fluid coming out of the cylinders.

The PS has its own pump and is a different circuit.

I will have to do a little research on the M7040 plumbing to see where to go next.

Dan

 

[TheOldHokie]

The PS has its own pump and is a different circuit.

I will have to do a little research on the M7040 plumbing to see where to go next.

Dan

There arent many places to use as test points in that plumbing.

Kubota wants you to use a "special tool" (adapter block) to connect a flow meter to the outlet flange on the pump.

There is also a joint in the delivery pipe that looks like you could hook up there with a simple hydraulic fitting. That would be my first choice.

In either case if you dont happen to own a high dollar flow meter you also need to construct a pressure test rig from some hose, a needle valve and a pressure gauge. Pretty simple. You up for that much work?

Dan