3-Point Hitch Kubota M4900 3PH lift arms cycling up and down

[TRM 1]

Recently purchased Kubota M 4900 with little over 600 hours on it has a problem with the 3 point hitch cycling up and down. with tractor running lift arms cycle up and down some especially if you use remote hydraulics such as picking up a wheeled disc. If you shut off tractor arms leak down approximately six to eight inches. Lift is strong and will pick up 4X5 round bales of hay without problem. Please guide me to what to check. The tractor does not have a front end loader and doesn't appear to have ever had one. The fluid level is full and the filters have been changed (By previous owner) I have wondered about the quality of the fluid as it does have some brake chatter and wonder if maybe Hyd. fluid is incorrect. I would appreciate any help you may give and thanks for your time in reading about my problem.

 

[TRM 1]

Surely somebody has a idea to help out the new guy

 

[rbargeron]

If the 3ph will lift and hold a heavy load, there's probably not a fluid quality issue that's causing the cycling. If you close the bleed valve under the seat does the hitch still sink when the engine is off? If so there may internal leakage in the lift ram.

 

[Chilly807]

In my experience, cycling or hunting means the position control valve isn't set correctly. Brake chatter is often caused by the wrong fluid, or so I've been told.

As for the control valve, this thread may give you some insight as to what's happening. It may not be your problem but it would be my best guess. It's a long read, but there's a few posts where that is described.

http://www.tractorbynet.com/forums/kubota-owning-operating/233308-l3400-3-point-hitch-adjustment.html

Sean

 

[luc]

I had the same problem on my Grand L2900 and I fixed it by taking apart and cleaning the control valve.
Not sure on your model , but on mine I had to remove a LOT of stuf to get to it.

 

[TRM 1]

Well I read through the other posts about the problems with the hitches on the smaller series of tractors and it seems the problem is similar to what I have going on with this tractor. I will have to do some more investigating on the tractor itself. This tractor is dropping the three point hitch when you use the remote hydraulics and then when you release the lever for the remotes the Three point hitch arms raise back up. When you shut off tractor the arms drift down and then when you crank the tractor they raise back up. Also the arms don't seem to raise as high as they should. seem like I read somewhere the little arm that is attached on the left side could be out of adjustment. Would that help the situation or change it any? If so how do you adjust it to work the way it should? Thanks for the replies. Hopefully I can figure out what needs to be done with the help I am receiving here.

 

[TRM 1]

http://www.tractorbynet.com/forums/kubota-owning-operating/137571-m4900-three-issues.html

Do you think the Last post made on the first page has any thing to do with my problem? although the arms on this tractor do not raise near as high as I think they should. You can grab them and move them up at least eight or ten inches with the tractor running with no implement attached. Could this adjustment be adjusted too long?

 

[Chilly807]

It sounds like a previous owner was fiddling with the position control valve and possibly the feedback linkage. Some of the internal adjustments have an effect on the raise height as well.

With the position control lever in the full raise position, there shouldn't be a lot of free play left in the arms. As an example, mine is supposed to have 10-15 mm free play at the upper arms when fully raised.

If it's like mine, adjusting the feedback will have no effect on the up and down cycling, but it should fix the lift height problem if you have one.

Your solution may be either taking it to a dealer for adjustment or getting a shop manual and doing it yourself if you're inclined that way. I have no idea which valve is in the the M4900, Kubota uses at least 10 different valves for their line of tractors.

Sean

 

[TRM 1]

well I guess I will try to adjust the feedback lever first and see how that goes when I get a chance. Thanks again for all the help so far.

 

[rbargeron]

..... This tractor is dropping the three point hitch when you use the remote hydraulics and then when you release the lever for the remotes the Three point hitch arms raise back up.......

Sounds like the remote valve doesn't have power-beyond going back to the hydraulic block to power the 3-point hitch. Without it, the remote circuit and the 3-point circuit share the supply and they interact.

How many hoses does the remote valve have? If it only has 4 (supply, exhaust and 2 work ports) then it needs a 5th hose between the valve's pb port and the hydraulic block. That's how a FEL valve would be plumbed. Power-beyond provides independent supply pressure to both so one doesn't affect the other.