3-Point Hitch Jinma 3 point hitch problem

[Leejohn]

This is not your valve, but you can see PB fitting and how it is used.

 

[Dickinson]

I'm not familiar with your tractor, but you mention high pressure and low pressure hydraulics. Do you mean that your tractor has two different pressure systems? That's a new one on me (except for power steering). As far as power-beyond goes, there is a cartridge that fits inside the valve body and is held in place by a special fitting that allows hose attachment.

Thanks for the reply. If you look at the first picture. the two hydraulic lines coming off the bottom of the hydraulic assembly for the FEL, one is low pressure or return to the tank pressure and the other is the same pressure but goes directly to the 3pt hitch control valves. This is not enough pressure to even make it through the 3 pt hitch control valve. But if I take the bottom right hydraulic line off the bottom and plug that hole and move it up to the high pressure formally plugged port. The 3 pt. hitch works by using the FEL control handle but then the FEL will not operate. I just moved it up to that port to verify that it was indeed a pressure problem coming from the original connection point at the bottom of the hydraulic assembly.

 

[Dickinson]

This is not your valve, but you can see PB fitting and how it is used.

Thanks for that info. I can see how the PB works. It looks like I may need a whole new control? Just odd how I have two lines coming off the bottom (tank lines - one definitely has a "T" mark) I even tried switching them thinking maybe someone crossed them by accident at some point. That made no difference.

 

[Leejohn]

Look in the port that is not marked, if it has threads make sure there is not a pipe plug in it. Some valves do use a pipe plug to give you PB. If you just see a hole with threads then you do not have PB.

 

[Bob Rooks]

Thanks for that info. I can see how the PB works. It looks like I may need a whole new control? Just odd how I have two lines coming off the bottom (tank lines - one definitely has a "T" mark) I even tried switching them thinking maybe someone crossed them by accident at some point. That made no difference.

I should have mentioned this before, but many hydraulic valves will have two return lines to the reservoir (neither of which are pressurized) - a return line from the cylinders and pump flow-through (open center system), and a valve leak-off line.

 

[quicksandfarmer]

These tractors are normally not plumbed with power beyond. Normally the 3PH is fed from the output of the FEL valve. It shouldn't work, but it does.

The thing you need to understand is that the FEL is an afterthought on these tractors, and it was cobbled in. The original hydraulic circuit is pump to 3PH to return. I implore you: stop moving hoses around, you're just making yourself crazy. Just get the FEL valve out of the picture. There should be one quick-attach coming out of the pump to the FEL valve, and one coming out of the FEL valve. With the tractor off, disconnect both of them, and then connect the pump directly to the 3PH. Then start the tractor. If the 3PH works now, we can start figuring out what's up with your FEL valve. If it doesn't work, we can work on the 3PH.

Did you check if the 3PH is being bypassed to the rear hydraulic remote?

I noticed in the picture that you had the draft control off and the link to the draft control disconnected. The 3PH absolutely will not work with that link disconnected.

 

[Dickinson]

Thanks for you comments and help!

Yes this tractor was set up with the output of the FEL valve feeding the 3pt. The former owner claims the 3pt. worked but stopped.

The draft control picture was one I took early on and included that picture thinking it may help give an idea of what I had for equipment. The tractor is actually located on my wood lot 60 miles from home so I took as many pictures as I could. All linkages and controls have been placed back in their original positions.

The 3PH is not being bypassed to the rear hydraulics.

I will try the connection that you recommended and let you know what happens.

thanks!

 

[Dickinson]

Thanks for you comments and help!

Yes this tractor was set up with the output of the FEL valve feeding the 3pt. The former owner claims the 3pt. worked but stopped.

The draft control picture was one I took early on and included that picture thinking it may help give an idea of what I had for equipment. The tractor is actually located on my wood lot 60 miles from home so I took as many pictures as I could. All linkages and controls have been placed back in their original positions.

The 3PH is not being bypassed to the rear hydraulics.

I will try the connection that you recommended and let you know what happens.

thanks!

That connection worked! Pump direct to the 3 pt.

 

[Dickinson]

That connection worked! Pump direct to the 3 pt.

 

[quicksandfarmer]

That connection worked! Pump direct to the 3 pt.

OK, now we're getting somewhere. So the problem is with how the FEL valve is plumbed.

The "normal" Jinma way of plumbing that valve is that the pump connects to the input, and the output of the valve goes to the input of the 3PH. When the valve isn't doing anything the fluid flows straight through the valve, and the 3ph works like the valve isn't there. If you were to lift the 3PH and the loader at the same time you could damage something, but I've had my tractor for ten years and haven't done that.

The "normal" everybody-but-Jinma way of plumbing that valve is to enable the power-beyond port on the valve. Pump goes to the input, and there are two outputs -- "unused" hydraulic fluid (ie at pump pressure) comes out of the power-beyond, and "used" fluid (at low pressure) comes out of the output. The power-beyond goes to the 3ph, and the output goes to the hydraulic tank (under the seat). The reason Jinmas aren't normally plumbed this way is that most don't have an opening on the tank to receive the "used" hydraulic fluid (because the FEL wasn't contemplated in the original design).

The first question is whether your valve has power-beyond enabled. If it does, you'll have an odd number of hoses -- input, output, power beyond, and two for each cylinder controlled. If there is no power-beyond you'll have an even number of hoses. The next question is to identify all of the hoses, and make sure they're going where they should be going. Post back and I'll help with that.