3-Point Hitch JD650 3pt hitch no control over arms. Help!

[BCinMI650]

So the little tractor has come a long way. Front end loader. Roll bar. Swapped the turfs for ags (on the turf rims so these things are huge). All new filters and fluids. It is running beautifully. But I am still not happy with the 3pt control. The total range of motion is great. I can lift all my implements plenty high without hitting the relief valve now (previously i would get 6 off the ground and it would be screaming and kill the tractor). And I have way more control than I used to, but it is still not a linear relationship between rock shaft and 3pt. I get very jerky upward movement. It is much smoother when the tractor is idling around 1000 Rpm. Soon as I ramp up to 1800-2000 for actual work, it gets jerky. Does not matter if it is a 250lb rake, 450lb box blade or just the draw bar. If I move the lever, it jumps, forcefully, and catches itself. The previous owner said he was trying to lift large round hay bales with a 3pt spear and no matter what he did, he could not get it to lift high enough for what he needed, so I am wondering if he tried to adjust something and messed it up. The other thing I have noticed is the little piston that comes out from under the seat (facing the rear of the tractor) and makes contact with the feedback lever only seems to come out maybe 1/4 to 1/2 inch and there is no contact for the rest of the time while the rockshaft lever is traveling. I do not know if that is correct or not, it just seems like there should be contact throughout the motion.

Any thoughts would be appreciated

 

[beenthere]

The other thing I have noticed is the little piston that comes out from under the seat (facing the rear of the tractor) and makes contact with the feedback lever only seems to come out maybe 1/4 to 1/2 inch and there is no contact for the rest of the time while the rockshaft lever is traveling. I do not know if that is correct or not, it just seems like there should be contact throughout the motion.

Have you looked at the parts involved to see if all are there and none missing?
Is this little piston you speak of item key#13 ?

 

[BCinMI650]

That is it yes. Lever down all the way, no contact, obviously no control when the lever is coming up until it makes contact with piston (Item#13), but once contact is made (maybe 1/2 - 2/3 of the way up the travel) its kind of a jerky motion until the lever is fully raised and the piston (Item #13) is depressed. Even when fully raised, the piston (Item#13) still sticks out about 1/8 - 1/4 inch (which I'm sure its supposed to given the design on the piece pushing on it) so it feels like the contact should be made earlier to give more precision throughout the motion.

 

[BCinMI650]

example of first contact and lever position

What is odd is that on the parts catalog, or tech manual, I can't find reference to the screw above my plug (Item #1) nor is it present on any used valves on ebay. see picture

 

[CADplans]

The only info I can offer is that my JD650 three point hitch goes up and down, and a VERY nice speed,,
and it will position respond like the 3PH on a $70,000 tractor,,

So, at least now, you know that is should work.

I do not have a loader,,
I would bet that the loader hoses could be incorrectly connected,, causing all sorts of 3PH issues.

The tractor has an open center hydraulic system,, the different hydraulic systems have to be connected in series.
If one is connected wrong,, everything else down stream will respond incorrectly,, also,,

 

[beenthere]

Good thought on the FEL system.. maybe try disconnecting the FEL and see if it has any effect on the 3 ph..

 

[BCinMI650]

CADplans, thanks for rubbing it in... could I bother you to check for or snap a picture of the rockshaft control valve to see if it has the screw above the plug like I mention above?

Would I need to remove the plumbing for it or just disconnect the quick connects? The control unit was already on it when I bought the tractor, as it controls the 4 way plow that came with the tractor (when I pulled the FEL out of a junkyard in Alabama I ended up with a spare unit)

 

[BCinMI650]

And actually if you are feeling generous, A picture of the piston when your rockshaft lever is fully depressed... so many things were out of adjustment on this tractor when I bought it (first tractor purchase, did not know what to look for, did not have a clear vision for what and how it would be used, totally on me, but I like the little bugger) that I would like to get back to square one.

 

[CADplans]

CADplans, thanks for rubbing it in... could I bother you to check for or snap a picture of the rockshaft control valve to see if it has the screw above the plug like I mention above?

Would I need to remove the plumbing for it or just disconnect the quick connects? The control unit was already on it when I bought the tractor, as it controls the 4 way plow that came with the tractor (when I pulled the FEL out of a junkyard in Alabama I ended up with a spare unit)

Nope, I do not have the screw,, that screw has to be part of the "power beyond adapter" (I have no idea what the "correct name for it is)

The "power beyond adapter" offers the needed ports to connect the loader valve to the tractor,, there has to be three hoses connected to the loader valve.


If you disconnect the loader valve correctly,, by connecting the correct hoses together, that would help to determine if the loader is at fault,,
I know nothing of the loader hydraulic connection, other than typical hydraulics.


On a side note,, I do have the little red lever on the side of the valve,,
mine is facing forward, yours appears to be rotated to point towards the rear?

I have no idea as to the function of that red lever,, Do you know what it is supposed to do?

 

[BCinMI650]

I believe that is the rate of drop lever. I have not fiddled with mine too much but I should. I do not know which way does what but I know It controls how fast your 3pt drops. My goal is to make sure I am not breaking concrete when I set down implements.

I bet you are right about the power beyond stuff. I will have to research it more. I am not 100% sure I have the stuff to plumb it without the FEL.