M Series 3 Point Drifts Down

[doctormdds]

My 2007 Kubota M7040 is having 3 point problems. With the tractor running, I can lift an implement with the 3 point and it will gradually begin to drift down. After it drops to a certain point, the hydraulic system will pick it up again. This happens over and over again. If I close the flow control valve (the little round know on the floor which adjusts how fast an implement will fall) it will hold but then I can't let the implement down. Fluid level is good. Any help you can give me will be appreciated.

 

[North Idaho Wolfman]

It sounds like a feed back lever is out of adjustment.
I have the service manual if you would like a copy of it.
Just send me a PM with a Email address and I'll send it over.

 

[Tx Jim]

The problem you describe is called hyd hiccuping. Sounds as if rockshaft seal(internal piston or external cylinder) or control valve is leaking and when enough oil is lost then 3 pt corrects it's height.

 

[doctormdds]

The problem you describe is called hyd hiccuping. Sounds as if rockshaft seal(internal piston or external cylinder) or control valve is leaking and when enough oil is lost then 3 pt corrects it's height.

What is a rockshaft seal or control valve? How do I fix these? While I'm mechanically inclined, I've never owned a tractor until I bought this one new in 2007!

 

[North Idaho Wolfman]

Your tractor has 2 external cylinders, so you wouldn't have a problem with internal piston leaks, you could pull the 2 vent tubes off of the top of the 2 lift cylinders and see if it's leaking past the seals on your lift cylinders.
I'll be sending you the manual then I can point you to the right pages and pictures.

 

[Umizedme]

I know this is an old thread, but I too am experiencing this problem on my b7800 with approximately 800 hrs.
Any help will be greatly appreciated!

 

[TheOldHokie]

I know this is an old thread, but I too am experiencing this problem on my b7800 with approximately 800 hrs.
Any help will be greatly appreciated!

First thing to suspect is a leaking lift cylinder.

Dan

 

[Umizedme]

First thing to suspect is a leaking lift cylinder.

Dan

Thanks Dan. After suspecting how do I confirm?

 

[TheOldHokie]

Thanks Dan. After suspecting how do I confirm?

Dont know the answer. Ideally you would like to watch from below for signs of oil leaking from the top. Ufortunately Kubota doesnt provide any inspection covers....

Dan

 

[Zimcocomp]

It sounds like a feed back lever is out of adjustment.
I have the service manual if you would like a copy of it.
Just send me a PM with a Email address and I'll send it over.

It sounds like a feed back lever is out of adjustment.
I have the service manual if you would like a copy of it.
Just send me a PM with a Email address and I'll send it over.

This sounds similar to my problem except mine happens in faster cycles. Also was grading our road today and noticed the FEL drops a little when the 3 point is bouncing. I graded our road by mainly using the hydraulic top link for height adjustment. Not too bad for an 80 year old. Thanks for your suggestion about adjusting the feed back rod, only I can't loosen the inner nut to even start. Is there a special tool to reach it? Thanks for your help.

 

[PoTreeBoy]

If it stays up with the lowering speed knob closed, the cylinder seal is not likely the problem.

 

[TheOldHokie]

If it stays up with the lowering speed knob closed, the cylinder seal is not likely the problem.

Good thinking - I forgot about the lowering speed valve.

CORROLLARY

If it drops with the engine off and valve closed it is likely the cylinder seal.

Dan