John Deere 2120 3PT Hitch Raises up on its own?

[bigblock76]

Does anyone know why the 3 point links would slowly raise up under no real load? If I'm using the snow blower or bush hog and never look back I wouldn't be doing much of any work because as I drive, the links slowly rise up and I constantly need to lower the lever again to bring them it back down.

Not sure if this is related or not, but when I just the tractor off and if I had the arms raised, they will drop down in the matter of 10 mins.

Has anyone heard of this one before?

Mark

 

[jd110]

It sounds like you might have 2 separate problems. If the hitch rises on it's own and the control lever is rising also, you have a problem with the friction washers on the lever not working right. There should be 3 flat washers there with 2 spring washers sandwiched between the flat washers that acts as a "brake" to hold the lever in position.
For the hitch leaking down quickly, you probably have worn or blown seals in the rockshaft valves and piston. The rockshaft housing needs to be removed to access those.

 

[EMcPhee]

When the tractor is shut off it will decend as the pressure is relieved. I put it down any ways to relieve the strain on the rockshaft-- call it setting the anchor.

 

[bigblock76]

It sounds like you might have 2 separate problems. If the hitch rises on it's own and the control lever is rising also, you have a problem with the friction washers on the lever not working right. There should be 3 flat washers there with 2 spring washers sandwiched between the flat washers that acts as a "brake" to hold the lever in position.
For the hitch leaking down quickly, you probably have worn or blown seals in the rockshaft valves and piston. The rockshaft housing needs to be removed to access those.

Yes, as the links rise, the lever rises also. From what you are describing, I should be looking at #10 & #11 on this diagram to correct it? Sounds easy enough.

As for the links lowering as the tractor is shut off. I'm assuming it shouldn't drop in a matter of minutes at best. Sometimes I raise it and want to keep it raised so I can work under the bush hog, clean the deck for the end of the season type of thing. Yes I do support it with blocks so I am not relying on the tractor for safety while I work on it. But it drops at a fast rate which doesn't seem normal.

How hard is it to change the piston o-rings? Once the seat comes off, then what?

Mark

 

[Tx Jim]

bigblock76
On 3 pt lowering when engine is stopped with 3 pt raised,engine running look inside hyd filler hole for spraying oil. JD utility tractors such as yours have a history of the control valve o-rings leaking. It's also possible the control valves are adjusted too tight which adjustment can be altered without removing RS housing.

 

[bigblock76]

bigblock76
On 3 pt lowering when engine is stopped with 3 pt raised,engine running look inside hyd filler hole for spraying oil. JD utility tractors such as yours have a history of the control valve o-rings leaking. It's also possible the control valves are adjusted too tight which adjustment can be altered without removing RS housing.

Hi Tx Jim,

Where is the adjustment so I can check it? Can it be done without removing the seat cover?

Mark

 

[bigblock76]

bigblock76
On 3 pt lowering when engine is stopped with 3 pt raised,engine running look inside hyd filler hole for spraying oil. JD utility tractors such as yours have a history of the control valve o-rings leaking. It's also possible the control valves are adjusted too tight which adjustment can be altered without removing RS housing.

I do lower them when I shut the engine off, but the reason I want to chase this is because I feel that I am losing pressure and its also nice to keep the bush hog up to service it sometimes.

 

[Zebrafive]

I found changing the "L", "LD", and "D" lever makes a difference in the 3pt raising on its own. I just don't recall where I ended up setting mine.

 

[Tx Jim]

Hi Tx Jim,

Where is the adjustment so I can check it? Can it be done without removing the seat cover?Mark

IIRC you need to remove plug(parts key #14) in RS housing to access adjusting screw(parts key #9) on linkage.

 

[bigblock76]

IIRC you need to remove plug(parts key #14) in RS housing to access adjusting screw(parts key #9) on linkage.

Hi Tx Jim,

What result should I expect to change by turning it in vs turning it out so I can figure out what to look for when I adjust it?

Mark

 

[Dizno]

Just a few more comments for what they are worth - I had a crack in the housing of my 1020 which has the same rockshaft housing. Water got into the oil and one cold morning last winter, I started up the tractor only to have a very loud bang wake me up. The rockshaft had come up and would not stop coming up. My questions are really threefold:

-have you pulled the plug to see if there is water in your oil?
-does this only happen in the cold weather or also in warm weather?
-what kind of oil are you using? I had put Mobil 1 hydraulic oil in, if i remember right. I should have stuck to JD oil for correct viscosity.

I did replace the housing on the tractor. It has been a year but I think you take the seat off, there a very short hose from the housing to the hydraulic control valve on the side, and you take the shield off by the shifters, the rubber covers on the shifters, and the two rear arms (one bolt on each side). You should use a engine hoist or something like that to lift it off. It is kind of heavy for one person to take off. Oh, there is also a wire you need to take off - the neutral safety switch which is under the shield you take off by the cover.

The rockshaft assembly bolts into the housing. Likely if you brought this in to a mechanic, they would fix this all up and you would save a stack by taking it off and putting it on. I did all this and it worked all spring. Then the 3pt became weak - could not pull out the posthole auger out of the ground. I had not time and dealership pulled it off, and there was an o-ring that had failed. It was $1,000 bill. The challenge is the sensing. If it is not set right, it doesnt work well. I do not know how this works.

Just some additional thoughts. Now when I shut the tractor down, I put the 3pt in the middle or down position. I warm up the tractor some before I move the rockshaft. The old 1020 has who knows how many hours - likely 4000 or more and the rockshaft settles real quick as well. My 1030 only has only 440 hrs - it is like new and i don't think the rockshaft settles very quick at all. There is a mechanic by Elora who knows alot of these tractors and he was/is a certified JD mechanic who knows these things and fixes tractors sometimes during the winter in his shed as he was trained on this vintage of tractor although he no longers works at the dealership. Maybe he could help.

 

[Tx Jim]

Hi Tx Jim,
What result should I expect to change by turning it in vs turning it out so I can figure out what to look for when I adjust it?
Mark

The adjustment screw has a countersunk head so if I'm thinking correctly( it's been since the late 80's since I've adjusted the RS valves) turning screw CW increases clearance & CCW decreases clearance.

 

[bigblock76]

Thanks to all who responded here. Looks like it was the friction washers not binding the leaver tight to the plate. The leaver does move up with the 3pt links so that was it. Thank you again.

Not sure if I should start another thread on this next symptom but it is related... The hitch leaver only seems to start to raise the links on only using the top 1/3 of the throw that it has to move. Is that normal? Doesn't seem to be, but also not sure what I can do to adjust it so that the lever starts to move the links sooner, thus fully using the throw that it has.

Any ideas?

Mark

 

[Tx Jim]

Put the L/D lever under the seat in "D" if it's not already there. If that doesn't solve your tractors 3 pt control problem then L/D mechanism will require adjustment as outlined in a JD service manual. .

 

[bigblock76]

Thanks Tx Jim. I will check that out this weekend.