3-Point Hitch Why 3Pt Does Not Maintaining Elevation Set

[swmich42]

When under load, 3pt allows implement to fall slightly, (1-4 inches) then corrects itself, and brings the implement back to where it started. What would cause this, and how to correct? Hydrolics are not something I am familiar with.

 

[3RRL]

Has it always done this or did it just start doing it recently?
Hydraulics moving like that, or a jerking motion, or even slow behavior are generally because of low fluid level. Also check for obvious leaks. A plugged suction screen or return filter would affect performance too. So I would check the easy things first ... leak and fluid level and clean the filters. Symptoms are more apparent at low roms than at high rpms. Once the fluid level is correct, and your filters are clean, try it again.

If the problem persists, then it could be worn "O" rings or glands in the hydraulic 3pt cylinder.
Another thing to check is your position control lever. Is the lever moving (creeping down) while you are working the tractor? It may need to be tightened a bit to stay in the position you put it?

 

[cspot]

What year/tractor/model do you have? That will help someone diagnose the problem. Some of the old tractors did not have good three point hitch systems and wouldn't maintain elevation very well.

 

[swmich42]

2000 John Deere 4700 4WD Hydrostatic, with 100 hours. Serviced last spring, all fluids changed. I will check fluid level. I have not noticed this until I recently attached box blade. Until then, I did not have any implements to try.

 

[tchmango]

Had the same thing happen a couple of years ago. Went through the same set of checks. No joy. Was still in warranty and took it in. Was some type of divert valve that was not working properly. Nothing major. Good luck.

 

[swmich42]

Thanks tchmango. I will check the fluid level. If that does not correct, I will inquire with my dealer, about how to fix.

 

[kebo]

2000 John Deere 4700 4WD Hydrostatic, with 100 hours. Serviced last spring, all fluids changed. I will check fluid level. I have not noticed this until I recently attached box blade. Until then, I did not have any implements to try.

Is 100 hrs right??? Geez, that's just 10hrs a year! That tractor is just now getting broke in good lol.

 

[beenthere]

Do you have the power beyond on this tractor?
Just in the last few days, I think there was a JD 4600 member with similar problem. Disconnected and reconnected QC's and solved his problem.
http://www.tractorbynet.com/forums/...ing/182403-jd4600-hydraulic-problem-help.html

Here is a troubleshooting chart. Hope it isn't a faulty rockshaft control valve, and assume the position of the lift control lever isn't moving.

 

[swmich42]

Thanks beenthere. I quick quoted MD3 on his issue. I am new to the tractor maintenance and or troubleshooting process, so you will have to forgive my ignorance. But where would the Quick Connects MD3 references be located? Since I do not have a loader, I am unfamiliar with QC's for a 3-point, if in fact there are any. The issue I have is exactly as MD3 describes.

 

[beenthere]

I noticed you had asked MD3, and see his response.

What is the history of your 4700? New to you, or had it since new in ?? year?

If new to you, then you may get your Deere dealer to run the serial number and learn what mechanical history it has gone through. Special note to any hydraulic work possibly done, or not done. A bit surprised it doesn't have a loader (FEL).

 

[Soundguy]

I wouldn't think fluid level issues ( at first anyway.. though it surely don't hurt to check..). it's be thinking more leakdown and circuit regeneration...

soundguy

 

[swmich42]

Soundguy, Thanks for the tip. Can you describe how "leakdown" and or "circuit regeneration" occur, how to tell if my problem is a result of either of these descriptions, and how best to correct?

 

[swmich42]

I checked service history of tractor. There had been only general fluid change service. I purchased this machine with only 94 hours. Original owner had set up this machine to accept a FEL, but intended to purchase this later. He pulled a four wheel cart with field debris off the drawbar. The 2" ball was the only spot on the tractor that had any paint scratched or looked used. PTO has still never seen a PTO shaft. Unfortunately the original owner passed away. His 220 acres is still up for sale by his estate.

 

[Soundguy]

leakdown.. IE. leaks in the cyl side of the lift circuit. perhaps a relief valve that is sticky.. or the piston/cyl seals.

circuit regeneration refers to position control.. IE.. when the leak makes the lift drop to the point where the position control corrects the lift to the original height by opening the control valve and adding more oil to the cyl.. thus if the leak is bad.. you could get a bobbing effect.. leakdown then regeneration.. over and over..

i don't know your specific machine.. or what it uses for a 3pt lift control valving.. etc.. just speaking in general here.

soundguy

 

[swmich42]

I was interested in how difficult it is to diagnose and correct the leakdown and circuit regeneration issue I am having. It has not become worse. Just interested in not paying $100's to the dealer to perform something that I could do.

 

[Soundguy]

first you must locate the laek. if that machine has access covers to the hyds section I'd look in with a mirror and see if you have fluid leaking past the cyl.. next possibility would be at a control valve and then a check, safety, and relief valve.

soundguy

 

[Snaker]

When under load, 3pt allows implement to fall slightly, (1-4 inches) then corrects itself, and brings the implement back to where it started. What would cause this, and how to correct? Hydrolics are not something I am familiar with.

I'm probably out in left field on this, but you say that you'r not familar with the tractor. Is there a chance that you have whatever additional controls that 3 pt system may have in a wrong position? Did you go through the operators manual?

 

[Chilly807]

I'm probably out in left field on this, but you say that you'r not familar with the tractor. Is there a chance that you have whatever additional controls that 3 pt system may have in a wrong position? Did you go through the operators manual?

I'm wondering if it has draft control or not. It probably doesn't, but if it does that will affect the 3 point height as the load changes if it's set to active mode.

Sean

 

[Chilly807]

I did a quick search for the JD 4700.. apparently draft control was an option. Yours may or may not have it.

Sean

 

[swmich42]

Thanks for the input. My 4700 does not have draft control. Sounds like I need to go into JD's site, and review any diagrams which would help me check for fluid leaks.