L3400 3-point hitch adjustment

kubotacres · Feb 7, 2012

I'll give my dealer a call tomorrow and see if I can get a detailed description on what/how adjustment was performed to my hydro control valve. Not making any promises they will let me know....

big e · Feb 7, 2012

So in this case the "lowering speed knob" does not smooth out the 3-point jerky-ness?

k0ua · Feb 7, 2012

big e said:
So in this case the "lowering speed knob" does not smooth out the 3-point jerky-ness?

Nope, they are all smooth as silk going down. The Lowering speed knob is a valve that just adjusts the flow of the return hydraulic oil from the cylinder to the tank. From no fluid flow all the way to maximum fluid flow.
The hitch is a position control type, when raised slowly the hitch goes up in a series of jerky movements instead of smoothly. This has something to do with the position control feedback mechanism that is controlling the valving or something. This is what Sean is trying to find out. Not all units show the same amount of jerkyness, and some after adjustment seem to be very smooth. Hopefully Sean will be able to give us some more knowledge on this in the near future.

James K0UA

Bluegill2 · Feb 7, 2012

Good photos and info, man! Mine's not too bad, but I'd like to adjust it at some point.

A good member here sent me a pdf file of the valve which should help.:thumbsup:

Harvest Moon · Feb 7, 2012

Sean, Thanks so much for tackling this and even more for sharing. Maybe you can put this issue to rest and help Kubota learn something about solving problems helping customers. Best of luck to you!

Don't forget to free up your suspension seat while you have it apart, if it's frozen like so many are. -Harvest

Chilly807 · Feb 7, 2012

Ok, I made some initial measurements this morning and the adjustments are definitely not in line with the data I have.

A little bird (or three) told me what the dimensions should be for three of the measurements you use during set-up.

This should be 47.5 mm (1.87"). Mine is set at 48.5 mm (1.91"). I'm not so concerned about this one just yet, since I think it sets the valve position in relation to the control lever and the feedback rod. There is mention made that if you change this, be sure to also adjust the feedback rod.

This should be 16 mm (0.630"). You set it at that position by moving the control lever or rod to get a 16 mm measurement, then hold it there while you check another measurement. In effect, the instructions would read, "While maintaining a dimension of 16 mm in location "X", dimension "Y" should be "Z" mm.

I stuck a screwdriver under the feedback link to hold it in place and rotated the control rod to give me 16 mm (0.630")

This is where it gets interesting. The dimension here should be 0.1-0.2 mm (0.004-0.008") with a 16mm (0.630") gap between the plate and valve body. Mine measured 1.14 mm (0.045")... almost 10 times what it should be.

I guess you know I'm about to make some changes and see what happens.

Sean

weldermike · Feb 7, 2012

Great job so far, hope it works out great for your effort. (shoot a hoyt)

GolfAddict · Feb 7, 2012

I am on the edge of my seat here to see what happens - seriously.

The crazy thing is I don't even have one of these tractors! With having read the horror stories and watched videos of pretty ugly looking 3pt operation, I have somehow started to feel vested in hoping to see a fix for this...

teg · Feb 7, 2012

Chilly807 said:
...almost 10 times what it should be...

Sean, excellent job, hoping for the best. :thumbsup::thumbsup::thumbsup:

10 friggin' times! Holy Cow... Isn't one of the first things that you read in the Hydraulic Section says:

"IMPORTANT, Set screws and spool joints 1 are adjusted to VERY CLOSE ACCURACY." Is this kubota's best quality? ...and then to say that there is not a problem with their hitches?