Understanding 3 pt hitch and/or float on china tractor.

[bob112]

having no manuals I am trying to understand how the 3pt system should work to know if it has problems. This is on a Bison 25. There is a hard hitch point for the top link, then another almost hydro cylinder looking thing just above it with another clevis. I was originally thinking this was a slick top link adjuster but was told this was part of some float control sensing?

I have 2 3pt levers. Of course nothing is marked. There seems to be no rhyme or reason to when the levers will lift the implement. 1 up, 1 down, 1 half way, other up, slow, fast, etc. Obviously if that sensor is not working right or not hooked up, that could be an issue but I need to find out.

A manual would be super duper but even that is next to impossible to find.

 

[ovrszd]

I'll take a shot.

I'm guessing your tractor has "draft control". That would explain the other "almost hydro cylinder looking thing just above it with another clevis". That's where your top link would be attached if trying to use draft control. This is a system that senses pull on the top link assembly and transfers that force to the 3pt lift system. More pull, the system lifts the 3pt slightly. Less pull, the system lowers the 3pt slightly. This is used to give uniform depth control on attachments, most commonly, a moldboard plow. That's how a tractor is able to plow at a uniform depth thru varying ground conditions.

The draft control is operated by one of the levers you described. To lift the 3pt the lever would be raised. To lower the 3pt the lever would be lowered. When plowing for example, you would determine the depth you want to plow and mark the spot on the lever guide where you would lower the lever to each time, creating a repeat of the plowing depth. When not using the draft control the lever would be stored in the lowered position.

The 3pt lift is operated by one of the levers you described. To lift the 3pt the lever would be raised. To lower the 3pt the lever would be lowered. This lever "should" be "position control" operated. That means every time you located the lever in a certain position the 3pt arms will return to exactly that height. Locate the lift lever to a different position and the 3pt arms will return to that particular spot. Drop the lever all the way down and the 3pt arms will fall to their lowest position. Raise the lever all the way up and the 3pt arms will raise to their highest position.

A 3pt system has no "down" pressure. For example, if you have a rear blade attached and you lower the 3pt lever to it's lowest position the arms will only drop until the blade contacts the ground. There is no down pressure applied beyond the weight of the blade and arm assembly. A 3pt system does, on the other hand, have lift capabilities. When the lever is raised the 3pt arms will try to lift the weight applied to them. If the hydraulics are strong enough to lift the load, that's what will happen. If not, then the load will simply sit there.

Confused yet.

 

[bob112]

Been running 3pt tractors since I was a runt and my gut says there is something wrong with this machine. I can have the draft in any position and still do not get repeatable lift with the other lever. most of the time, it won't even lift at all. however, i was working on other things and started the tractor and because the lift lever was all the way up, it lifted the implement WAY up (higher than I have ever seen on a tractor, and it held there no problem.

Pretty much telling me the lift cylinder is working but something else is messed up.

Pics of another machine show a bracket connecting the hard 3pt top link connector to the sensor, then a central pivot clevis mount for the top link. I am wondering if the tractor can be made to function without this?

 

[ovrszd]

Sorry, I certainly didn't mean to imply you hadn't been around tractors. I just assumed it since you didn't understand the "other" toplink assembly. My bad.

I've attached a picture of my Ford's toplink setup. The top end of the bracket is fastened to the draft sensor, which is adjustable by taking it apart. The lower pins can be moved to increase/decrease the sensitivity of the draft control. Maybe your tractor is lacking this bracket or something similar??

With no markings how did you figure out which lever is the draft lever?

Maybe shoot some pictures and post them?

 

[bob112]

I guess I just have not been around draft control tractors, odd as that might seem. Right from ford 800/900 to ag tractors. I guess the question is, if that draft sensor is not hooked up, should the lift still work? My guess is yes because you can usually lift the lift arms without an implement on them.

Yes, no doubt the bracket that couples the rigid top link mount to the sensor mount is missing. what I have now is a top link that is just connected to the rigid mount.

Better question might be, what the heck is going on with the tractor?

 

[ovrszd]

Yeah, I think there's some issues other than the draft link.

I believe the lift should work whether the correct top link bracketry is there or not.

Hmmmm. Where to go from here??

Are you positive you have correctly identified the levers as to their function?? The draft lever should be in lowered position to use the normal lift lever. But even if it isn't I don't understand the sporadic behavior of the lift. Hmmm..

Edit: Forgot to mention, the older Ford tractors had draft control. It was activated by a small lever on the side of the transmission and then controlled by one 3pt lift lever. Also any AG tractor that was designed to handle 3pt tillage equipment would have draft control.

 

[bob112]

Well, I seem to be getting somewhere. It seems the bracket around the lift levers is adjustable! I rotated it back so the levers will rotate back further and it lifts consistently now. It lowers nice and smooth but up seems to be more on and off rather than progressive like it should be. I am not yet sure if the draft sensor is playing into that??

I did use a pry bar to play with the sensor and the lift responds to input so it works! Just need to get a nice progressive lift and get the draft link on and we are getting closer.

 

[ovrszd]

That's good news!!!! Hopefully you can get thru this without some serious mechanical repairs needed.

I don't think the draft sensor would have any affect on the smoothness of the lift when using the normal lift lever. My Kubota and Ford both have 2 levers. As long as the draft lever is in the lowered position the 3pt is not affected by draft at all.

Have you been able to find any pictures of your tractor to know what the missing link should look like?? And if so, is it something you can fabricate or hire someone to fabricate??

 

[bob112]

I own a machine shop but though I have seen a picture of one, I suspect there is a specific location for the top link hole to get the correct force to the sensor. The bracket seems to cheap to make.

On the draft lever, What the tractor is acting like is the second lever is more of a lift limiter. If I have it all the way down, it will not lift at all. The inner lever seems to set the lift, and the outer lever is the main lift lever. I would say it is far from working correctly but at least it lifts and holds right now. With the tractor off, it will hold all day.

 

[ovrszd]

Hmmmm. Trying to think of a situation where a "lift limiter" lever would be required?? I can't think of any.

When I'm at the farm this afternoon I'll play with my two tractors that have draft control. For example, I've never tried putting the main lift lever in the lowered position and then try to lift the 3pt with the draft lever.

Without being there, what I'm toying with is the idea that the lever functions are backwards from what you think they are?? What you think is the main lift lever is actually the draft lever?? Excuse my ignorance, just trying to think of a scenario where the results would be similar to what you are describing.

Good that it holds a load all day. That tells you the valves and cylinder are solid.