3-Point Hitch No lift in 3-point hitch

Egon · Mar 7, 2015

Yes I do have a tractor. I'm not going to take the backhoe off though.

Note the comment about point A/B
On the picture what happens to the implement if the top link is moved to the bottom hole.

LD1 · Mar 7, 2015

In the pic of the actual tractor, if the tl is moved to the bottom hole, you will loose lift force, because it causes the fork tips to move a greater distance (in relationship to the 3ph itself) than where it currently is in the top hole.

I'll see if I can throw together a simple model.

2458n · Mar 7, 2015

When you go to Orange tractor talks. they have a guy called service dept Vic. he is a real person. I figured out the time zone difference and called him one day from Ohio. Got the phone number for the dealership off of a sign out front of the shop. I used to have his cell phone number. He will tell you like it is with Kubota. Not a lot on the site but he really helped me.

LD1 · Mar 7, 2015

Here we have a simple cardboard contraption showing a fixed length toplink but two different positions. In position 1, the change of angle of the forks (using the desk edge as a guide) is minimal compared to position 2. Sure, position 2 starts out further from level. Which can be adjusted in the real world by lengthening the toplink. That's not the point. The point is the angle change. When the hitch is raised to the same location (black line on desk), position 2 changes angles to a greater degree.

While I didn't measure it, just guessing, it appears that position 1 may have started at 5* and ended at 10* from horizontal. While position 2 may have started at 10*, but ended at 25*. While those numbers may not be exact, it is clear to see that the angle changes much more.

And in doing do, with the length of the forks being constant, the tips move a greater distance (in relationship to the 3ph) with the toplink in the lower hole. Which requires a greater input of force for a given weight to lift.

LD1 · Mar 7, 2015

I have no idea why those loaded upside down. Uploading is bad enough from a smartphone let alone trying to fix that now.

Egon · Mar 8, 2015

Nice models.

The implement pivots around one point. The blue pin. The lift arm pivots about another point at the opposite end of the lower lever arm. The lift points will be between the two pins. ( A & B on the parts diagram. )

Put in the lift points and then draw the arcs that are subtended from start to finish.

spareparts1 · Mar 8, 2015

LD1 said:
I have no idea why those loaded upside down. Uploading is bad enough from a smartphone let alone trying to fix that now.

That happens to me a lot LD! Now worries! These pictures are very helpful! THANK YOU!

So yesterday... (Yes... Another question) I was offloading a few of those 900# alfalfa bales to put them under cover. I have a few friends stand of the forks in back so I don't turn the tractor over, lifting it off of the trailer and getting it to the carport. Anyway... At one point, I had to lift the bale a little to force the hay spear (I have one I put on the FEL) into the bale. When I tried to do this, the forks in back started this rhythmic jumping, to where my friends almost couldn't stay on. It... was... kind of funny to watch... :laughing:

This had never happened before... Not even when I first got the tractor... Seems like the pump is being taxed? When my hay guy puts a bale on his little Ford and loads up my trailer with the round bales, his 3ph forks don't jump like this. Could this be an adjustment thing? I am NOT letting my tractor go back to that shop, so either I need to figure out what is going on so I don't tear it up, or I live with it.

I've been bragging about how y'all have helped me so much! Hope that's Ok!

teg · Mar 8, 2015

There was someone who tried to adjust the 3ph valve to reduce the jerky 3ph, it work but the side effect was that the 3ph would drop an inch (if it had weight on it) and jerk the tractor around AFTER the FEL valve is activated.

That might be part of it...

Egon · Mar 8, 2015

The shakies as described might be a pressure set valve relieving, closing, relieving. Chattering. They may do this very quickly resulting in shakes as described. As you were only trying to lift a small amount the flow rate through the control may have been low enough to allow the chatter to develop. Full flow would have left it open.
It does sound as though you are operating at the tractors load limits.

Have you tried lifting a reduced load with the three point?

LD1 · Mar 8, 2015

teg said:
There was someone who tried to adjust the 3ph valve to reduce the jerky 3ph, it work but the side effect was that the 3ph would drop an inch (if it had weight on it) and jerk the tractor around AFTER the FEL valve is activated.

That might be part of it...

I think thats the answer. And if so, that sucks. IF they adjusted the 3PH valve too far, its position becomes totally dynamic and dependent on pressure. Makes for a smooth operating hitch, but anything else that changes pressure in the system changes pressure in that circuit and you see movement as a result.

I guess first think I would do is try to replicate the issue. Raise the hitch up, an keep an eye on it while you do some maneuvers with the FEL. Pushing into something, dumping, raising, etc. Just put it through its paces