Kubota L2800 3pt issue - need help

D60 · May 24, 2020

Hello TBN community, my tractor is a Kubota L2800 HST purchased new in '05. Presently only has about 450 hours on the meter.

Recently I lent it out and the notorious suction hose near the operator's right foot cracked. As a result all hydraulics were jerky/weird/questionable but they used it for the remainder of the day, adding fluid occasionally (they never fully understood what happened).

Anyway, I replaced the hose and re-filled with fluid. Everything is mostly ok but I noticed if you take the 3pt lever (at the operator's right hip) all the way up you can hear the pump whine like it's bypassing? or blowing off? When the pump sounds like this the FEL is also slow to move in certain directions.

I was able to temporarily remedy the pump noise when the 3pt control is all the way up by simply putting a 1/4"-20 bolt and nut in the slot for the control lever - you only need to limit the uptravel of the lever by literally a 1/4" or less to make the noise go away. However the bigger annoyance is that the 3pt is VERY slow to drop now, which is annoying if you're doing repeated blade work in my case.

So, does anyone have any idea why I can't max the travel on the lever for the blade (er 3pt) to go UP without getting noise (bypass?) and why the 3pt is so slow to fall now?

I'm mechanically inclined but not great with hydraulics (obviously), so any guidance would be much appreciated!

Thomas · May 24, 2020

I had L2800HST the control needed to be turn completely open for smooth operation and no noise.

Roadworthy · May 24, 2020

There is a valve that controls the speed of lowering the three point. It should be between your feet, perhaps slightly under the seat. There is probably an adjustable stop on the three point control which can set how far you can lower it. I can't help with the noise.

Dave M7040 · May 24, 2020

Attached to the left upper lift arms is a link called a feedback link.

Its purpose is to open the 3 pt valve once the 3 pt hitch either reaches the top of its range or if it reaches a position control position.

It does this so the hydraulic pump is not continually discharging through the relief valve and overheating thee hydraulic system.

You need to read the material I have attached and then try and understand the adjustment procedure.

As other have said, your machine will have a knob to control the speed that the 3 pt arms can drop. Look at the attached illustration where I have identified this knob.

Dave M7040

Oldpath05 · May 24, 2020

On mine that knob only controls how fast the the 3-point goes down, has nothing to do with pump whine, I get that noise when I try to lift to much weight on the 3-point hitch. So when I try to lift to much with 3-point, the pump whines and the FEL wont go up. A few years ago I had that hose break, when it started leaking and everything went kinda jerky so I went down the tractor place and got a new one.

D60 · May 24, 2020

Ok you guys are all geniuses -- or more likely I'm an idiot....but it sounds better to say you're geniuses so we'll go with that.

I didn't know the knob existed but I barely cracked it and all is well.

I also had no idea about the feedback lever but it looks like that probably needs adjustment, too. I'll take a look at that next week to see if I can remove my homebrew bolt stop and eliminate the relief valve noise

Thank you all!