B7200 3 point hitch control

[Berry]

I had my 3 point hitch repaired at my local Kubota dealer. Everything was originally working at the time I removed the control I have change all the oil and cleaned all filters. The reason for the repair was leaks on the control arms that exit the body. New o rings where installed and the leaver is much more stable.
After installing the control back in, I ran the tractor for two minutes and rechecked my oil level. Topped up the oil and checked again. The oil level is up to the top mark on the dip stick.
\
My problem is the 3 point will not lift and I am curious about an air lock. I noticed on the top of the control is item 300 of the parts breakdown. a pipe plug looks like a 1/8 pipe in size ( I assume metric ). Is this Plug used to blead off air, and if so is there a procedure to blead off the air?

P.S. the Hydraulic steering is working and the tractor is operable.

Any help would be much appreciated.

 

[TheOldHokie]

I had my 3 point hitch repaired at my local Kubota dealer. Everything was originally working at the time I removed the control I have change all the oil and cleaned all filters. The reason for the repair was leaks on the control arms that exit the body. New o rings where installed and the leaver is much more stable.
After installing the control back in, I ran the tractor for two minutes and rechecked my oil level. Topped up the oil and checked again. The oil level is up to the top mark on the dip stick.
\
My problem is the 3 point will not lift and I am curious about an air lock. I noticed on the top of the control is item 300 of the parts breakdown. a pipe plug looks like a 1/8 pipe in size ( I assume metric ). Is this Plug used to blead off air, and if so is there a procedure to blead off the air?

P.S. the Hydraulic steering is working and the tractor is operable.

Any help would be much appreciated.

Not air and dont be tsking out unknown plugs.

I am trying to understand what was done. What "control" did you remove and what did you take to the dealer? Does not sound like the dealer got the whole tractor.

Dan

 

[Berry]

Not air and dont be tsking out unknown plugs.

I am trying to understand what was done. What "control" did you remove and what did you take to the dealer? Does not sound like the dealer got the whole tractor.

Dan

It was the control valve for the three point hitch and you are correct, they did not get the tractor, just the control valve. I call it the control valve because that is the name on the parts breakdown. Reference page 01T066 of the parts manual

 

[North Idaho Wolfman]

You do not need to remove anything to bleed it.
Is the drop speed control closed?

 

[TheOldHokie]

It was the control valve for the three point hitch and you are correct, they did not get the tractor, just the control valve. I call it the control valve because that is the name on the parts breakdown. Reference page 01T066 of the parts manual

I would start by verifying you are getting delivery of oil from the pump. Banjo joint on the right side of the valve. Also check the position control feedback linkage is properly connected. I assume the position control valve was sent alonfg with the main assembly.

Dan

 

[CoKid]

Barry don't feel bad if it was the drop speed control, I had cleaned out my cab and had moved it for one reason or another and forgot to move it back. Made me feel real stupid cause I know better and forgot to check. Made the call to the dealer too and got the same question.

 

[TheOldHokie]

Barry don't feel bad if it was the drop speed control, I had cleaned out my cab and had moved it for one reason or another and forgot to move it back. Made me feel real stupid cause I know better and forgot to check. Made the call to the dealer too and got the same question.

How does drop dpeed valve prevent the lift from coming up?

Dan

 

[CoKid]

How does drop dpeed valve prevent the lift from coming up?

Dan

Sorry read it wrong.

John

 

[N3BP]

Like Wolfman suggested, it might be in the "locked" position. Give it a couple spins CCW to see if that changes anything.

 

[Berry]

You do not need to remove anything to bleed it.
Is the drop speed control closed?

Good morning all. I am sure the drop speed valve is or was in an almost closed position from before the repair to slow the hitch down. Pouring rain here right now an unfortunately I have to work outside. I will make sure that valve is wide open to start then adjust accordingly.

 

[Berry]

I would start by verifying you are getting delivery of oil from the pump. Banjo joint on the right side of the valve. Also check the position control feedback linkage is properly connected. I assume the position control valve was sent alonfg with the main assembly.

Dan

Thank you, I will be doing both as suggested.

 

[TheOldHokie]

Good morning all. I am sure the drop speed valve is or was in an almost closed position from before the repair to slow the hitch down. Pouring rain here right now an unfortunately I have to work outside. I will make sure that valve is wide open to start then adjust accordingly.

That valve only controls lowering speed. It will not prevent the lift from raising.

Dan

 

[Berry]

That valve only controls lowering speed. It will not prevent the lift from raising.

Dan

That makes sense. In reference to your last post, I sent in the Control valve only. as it was the only thing leaking. I am not sure what the position control valve looks like. I haven't found that description in my parts breakdown.

Don

 

[Berry]

That valve only controls lowering speed. It will not prevent the lift from raising.

Dan

Just to be clear, The only parts that went to dealer for repair was item 020 control cover with shaft control levers item 340 and 360 still installed to have the o rings replaced as they were the only things leaking. The control leaver that was attached to the control arm was very sloppy. This lever is much firmer and there is no leak around the shafts. With that, I'm not sure at this time if there is any oil there to leak. After this storm passes, I will loosen off the banjo bolt to be sure oil is getting to the control.

Don

 

[TheOldHokie]

That makes sense. In reference to your last post, I sent in the Control valve only. as it was the only thing leaking. I am not sure what the position control valve looks like. I haven't found that description in my parts breakdown.

Don

I was actually talking about the parts in the box behind the main valve body.

In any event your first priority should be making sure you are getting pressurized oil at the valve inlet. No oil flow no lift. That would be the simplest answer and easiest to address.

The valve on the B7200 is more complicated than most. It utilizes an unloading poppet that controls the flow of pressurized oil going to tank in neutral and entering the spool when lift is commanded. I suggest you get a copy of the WSM for guidance on theory of operation and troubleshooting.

Dan

 

[Berry]

I was actually talking about the parts in the box behind the main valve body.

In any event your first priority should be making sure you are getting pressurized oil at the valve inlet. No oil flow no lift. That would be the simplest answer and easiest to address.

The valve on the B7200 is more complicated than most. It utilizes an unloading poppet that controls the flow of pressurized oil going to tank in neutral and entering the spool when lift is commanded. I suggest you get a copy of the WSM for guidance on theory of operation and troubleshooting.

Dan

Just a follow up, I backed off the drop speed valve by two turns to answer other members suspicions with no results. With the tractor running, I backed off the banjo bolt on the inlet and oil began to flow. I was waiting for the possibly of a high pressure leak and getting sprayed, no spray just a low flow.
The linkages all seem to be correct and connected

I also looked up the WSM I have, not a lot on this valve. I did find the oil flow direction (Hydraulic steering), not much more.

I'm starting to suspect I have done something wrong with the assembly of the control. It really looked so straight forward, maybe not and back to the drawing board.

 

[TheOldHokie]

Just a follow up, I backed off the drop speed valve by two turns to answer other members suspicions with no results. With the tractor running, I backed off the banjo bolt on the inlet and oil began to flow. I was waiting for the possibly of a high pressure leak and getting sprayed, no spray just a low flow.
The linkages all seem to be correct and connected

I also looked up the WSM I have, not a lot on this valve. I did find the oil flow direction (Hydraulic steering), not much more.

I'm starting to suspect I have done something wrong with the assembly of the control. It really looked so straight forward, maybe not and back to the drawing board.

Without a load on the circuit pressure at the inlet banjo is only a few PSI but at 800 RPM you should be getting a bit over 1 GPM of flow. I would be more confident you had flow if you had the pipe disconnected and could measure some real volume coming out of it. You could run the tractor for 30+ seconds with the pipe disconnected and no danger of pumping the tractor dry.

The WSM should have a detailed description of the valve construction, and operation. The main spool in that valve does not directly switch oil to the cylinder. It actuates two secondary poppets that do the actual switching

The unloading poppet is located at the inlet porr and is activated by a pressure differential created by moving the main spool to the lift position. If the unloading poppet is mechanically stuck in the unload position the lift is not going to work.

This is why its impossible for the dealer to test the rebuilt valve without the tractor.

Dan

 

[TheOldHokie]

Just a follow up, I backed off the drop speed valve by two turns to answer other members suspicions with no results. With the tractor running, I backed off the banjo bolt on the inlet and oil began to flow. I was waiting for the possibly of a high pressure leak and getting sprayed, no spray just a low flow.
The linkages all seem to be correct and connected

I also looked up the WSM I have, not a lot on this valve. I did find the oil flow direction (Hydraulic steering), not much more.

I'm starting to suspect I have done something wrong with the assembly of the control. It really looked so straight forward, maybe not and back to the drawing board.

Here is the description from my WSM. My apologies for the upside down pages - I don;t have time to fix that right now. Print it single sided and flip them over.

Edit 7/14: Page orientation fixed

Dan

 

[Berry]

Here is the description from my WSM. My apologies for the upside down pages - I don;t have time to fix that right now. Print it single sided and flip them over.

Edit 7/14: Page orientation fixed

Dan

Thank you Dan for the copies out of your WSM. These are definitely not in my copy of the WSM. I have a feeling that your copy has much more detail then mine. I downloaded a copy out of Kubota books for the B7200HST. I was also able to turn the pages around and print both sides.

The problem is solved, the 3 point hitch is now fully operable and here is what I have found out.

While trying to assemble the unit, I tried to assemble with the spool removed from the body. This would allow me to install the control lever into the two control arms. Then I inserted the spool into the valve body. So far so good until I attached the nut to the end of the spool. As I was tightening the nut down, I was unaware that by tightening down the nut, I was also turning the spool. By doing so, I turned the spool drive lever out of position in the two control arms.

I figured in order to prevent this, I had to assemble in reverse. With the spool in the body completely assembled with the spring and nut, and with the control lever in the right position. I placed a 14mm socked over the the nut, this would allow me to apply pressure on the spool and push it further out of the body. This then would allow me to delicately connect the control lever to the control arms. There is very little space to see and as the lever pivots on the spool, difficult to do. Then bolt the body to the valve cover.

The only way I knew i was successful at this stage was to turn one control arm which would also turn the opposite arm automatically. This was not happening before, which should have told me the spool lever was not engaged with the control arms.

Just for curiosity sake, I think I will close the speed lowering control right off to confirm weather this has any effect on raising the 3 point hitch.

Lessons learned the hard way, one I will not forget.

Thanks again for the copies of WSM and help from all at OTT.

Don

 

[TheOldHokie]

Thank you Dan for the copies out of your WSM. These are definitely not in my copy of the WSM. I have a feeling that your copy has much more detail then mine. I downloaded a copy out of Kubota books for the B7200HST. I was also able to turn the pages around and print both sides.

The problem is solved, the 3 point hitch is now fully operable and here is what I have found out.

While trying to assemble the unit, I tried to assemble with the spool removed from the body. This would allow me to install the control lever into the two control arms. Then I inserted the spool into the valve body. So far so good until I attached the nut to the end of the spool. As I was tightening the nut down, I was unaware that by tightening down the nut, I was also turning the spool. By doing so, I turned the spool drive lever out of position in the two control arms.

I figured in order to prevent this, I had to assemble in reverse. With the spool in the body completely assembled with the spring and nut, and with the control lever in the right position. I placed a 14mm socked over the the nut, this would allow me to apply pressure on the spool and push it further out of the body. This then would allow me to delicately connect the control lever to the control arms. There is very little space to see and as the lever pivots on the spool, difficult to do. Then bolt the body to the valve cover.

The only way I knew i was successful at this stage was to turn one control arm which would also turn the opposite arm automatically. This was not happening before, which should have told me the spool lever was not engaged with the control arms.

Just for curiosity sake, I think I will close the speed lowering control right off to confirm weather this has any effect on raising the 3 point hitch.

Lessons learned the hard way, one I will not forget.

Thanks again for the copies of WSM and help from all at OTT.

Don

Thanks for the update and description of the problem. Glad you got it fixed!!!

Dan