3-Point Hitch Jinma 3 point hitch problem

[Dickinson]

Jinma 604 3 point hitch wont lift
This is my first post. I've been using this site for information since I purchased a 2006 Jinma 604 that had several problems which I've resolved thanks to the vast knowledge of everyone on this site. One problem that I've been stuck on is the 3 point hitch will not lift. I've pulled the entire hitch apart and have gone full circle and currently I have the problem isolated to the Welvoir Hydraulic diverter assembly. The hydraulic block has 6 ports on the face of it with two ports under it that go to the Tank. I have a picture but I haven't figured out yet on how to upload onto this site. The 4 ports in the middle of the assembly go to the FEL. There are 2 plugged ports, one directly above the FEL ports and 1 below. Originally the tractor had 2 lines coming off the bottom of the hydraulic control assembly Tank ports - 1 to the reservoir tank and one into the 3 point hitch control valves - this was low pressure to both. I removed the hydraulic line that runs to the 3 point hitch control valve that feeds the 3 point hitch piston and connected that to the plugged port just above the FEL ports. When I did I finally got the 3 point hitch to go up however not by using the 3 point hitch control handle but by using the FEL control which left the FEL inoperable. Now I'm wondering if this is the wrong Hydraulic control with no power beyond port? The former owner claims the 3 point hitch worked but I'm wondering now. Thanks for any help!

 

[Bob Rooks]

Is there a draft control?

 

[Dickinson]

Actually I'm not sure it does. I didn't believe so but I just read a little about draft controls and that makes me wonder. There is only one control lever that operates the control valve for the 3 pt. hitch. There is also a max height linkage to prevent the hitch from raising too high. On the back of the three point hitch there is a large spring that just sits in a hole in the casting. Not sure what the function is. Like a shock absorb-er? Where do I look for a draft control? Thanks for replying by the way!

 

[quicksandfarmer]

The springy thing is the draft control.

The way mine works is there is a single lever. All the way down is hitch down, draft control on. As you raise the lever draft control comes off, and as you raise it past half way the hitch lifts. The metal piece to the right of the springy thing is the draft control link. When draft control is on, if you hit an obstacle the springy thing moves, which causes that link to move, which connects to the hydraulic control and causes it to lift.

If yours is like mine, the front end loader can be removed from the hydraulic circuit by disconnecting the quick-attaches and attaching them to each other. I think I see a quick-attach in the bottom of your first picture. I would start by taking that out to simplify things. The circuit should now go pump - power steering - 3pt lift - return to pump.

I see you have a hydraulic remote on the rear. That remote is controlled by the 3pt hitch control. There is a valve under the seat that switches whether hydraulic fluid goes to the lift or to the remote. Make sure that valve is sending fluid to the lift. You can attach a pressure gauge there, and switch the fluid to the remote, to see if the lift is getting fluid. Or you can do a crude test with a quick-attach and a bucket.

Do the power steering and front-end loader work?

 

[Leejohn]

By your 1st picture if that valve uses a pipe plug to give you PB then it's right. But if it has to have a PB fitting I couldn't see it. If it needs the PB fitting I don't think JC hose end would even hook to a PB fitting.

 

[Dickinson]

The springy thing is the draft control.

The way mine works is there is a single lever. All the way down is hitch down, draft control on. As you raise the lever draft control comes off, and as you raise it past half way the hitch lifts. The metal piece to the right of the springy thing is the draft control link. When draft control is on, if you hit an obstacle the springy thing moves, which causes that link to move, which connects to the hydraulic control and causes it to lift.

If yours is like mine, the front end loader can be removed from the hydraulic circuit by disconnecting the quick-attaches and attaching them to each other. I think I see a quick-attach in the bottom of your first picture. I would start by taking that out to simplify things. The circuit should now go pump - power steering - 3pt lift - return to pump.

I see you have a hydraulic remote on the rear. That remote is controlled by the 3pt hitch control. There is a valve under the seat that switches whether hydraulic fluid goes to the lift or to the remote. Make sure that valve is sending fluid to the lift. You can attach a pressure gauge there, and switch the fluid to the remote, to see if the lift is getting fluid. Or you can do a crude test with a quick-attach and a bucket.

Do the power steering and front-end loader work?

The power steering has it's own pump and the front end loader works well. In the first picture if I move the line off of the bottom right hand side of the hydraulic assembly (this line goes to the control valve that operates the 3 pt. hitch) and remove the plug on top of the hydraulic assembly and screw the hydraulic hose into this port, the 3 pt. hitch works with the FEL control handle. This proved in my mind that I wasn't getting HP hydraulic flow to the 3 pt. hitch control the way the lines are connected in the photo. I even pulled the plate under the seat that has the knob to adjust the 3 pt hitch drop speed. With all the hydraulic hoses connected as shown in the first picture, I have no flow through the port when I raise the control handle (with the plate off) that pushes on the piston. If I remove the hydraulic hose from the lower right side of the first picture and move that hose into the plugged port I get HP flow to the area where the plate was pulled. When I reinstall the plate the 3 pt hitch works but only by moving the FEL hand control. I have tried moving the draft control linkage back and forth with it disconnected from the draft control connecting point to see if maybe it was way out of adjustment. No luck and no flow to the top of the 3 pt hitch piston.

 

[Dickinson]

Yes I'm stumped. In the first picture the hose on the bottom left goes to the tank. The hose on the bottom right goes to the 3 pt. hitch control. Both are low pressure. As you can see from my other post the lift work using the FEL control if I move the bottom right hand hose up to the plugged port on the HP side.

 

[Leejohn]

Yes I'm stumped. In the first picture the hose on the bottom left goes to the tank. The hose on the bottom right goes to the 3 pt. hitch control. Both are low pressure. As you can see from my other post the lift work using the FEL control if I move the bottom right hand hose up to the plugged port on the HP side.View attachment 474592

Thats telling me the PB fitting is not there.

 

[Dickinson]

Thats telling me the PB fitting is not there.

So if the PB is not there, could the 3 pt hitch have every worked? What can I do to fix the problem?

thanks!


Sorry for the confusion. This 3rd photo is when I had originally pulled the hitch because it wouldn't lift. At the time I thought the piston in the hitch may be frozen in place. It was not. Everything on the tractor is back together now.

 

[Bob Rooks]

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.

 

[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.