John Deere 4020 3 point help!!

[Anonymous-0]

OK Bought this Tractor last year and noticed while useing it that the three point Hitch will not stay where I put it. Even when I put the Rock Shaft in the "D" position. It always sinks all the way down. If I lift it up, it goes all the way up fine. If I turn the Tractor off it will slowly just ease on down to the ground. The Hydrolics seem OK Cause it stears good and the Brakes are good. But it seems like I can't keep the 3 point hitch in a set position, no matter if the Rock shaft is at "D" or "LD" or "L".....Where do I look to try to trouble shoot this issue....

 

[Bob]

How long does it take to sink down?

If it drops fairly rapidly, most likely causes would be bad rings on the lift piston, or contol valve problems.

 

[Dairy Farmer in WI]

to me it sounds like your lift valves pump needs valves and orings. when you shut the tractor of and it sinks down, that is a sign that the hyd valves are leaky.
DF in WI

 

[Anonymous-0]

Is this something hard to fix?? How would I check this further??

 

[Anonymous-0]

Not that fast maybe over 5 min it is all they way to the ground...

 

[Bob]

As I said before, the lift cylinder is MOST likely the problem. It is NOT the pump.

If the hitch valve IS bad, special tools are needed to repair and set it.

 

[Anonymous-0]

where are these valvs located??

 

[Heat Houser]

So your three point only has all the way up or all the way down. In otherwords if you move the lever to some midpoint position, the hitch still goes all the way up (or down if that is the way you last moved the lever)

If the load shaft was removed to fix leaks,(common to do) the cam feed back roller may have snapped out of the feed back link. The hitch will not stop in mid range since there isn't any feedback for rockshaft position.

The slowly leaking down could be due to the thermal relief, raise/lower balls not seating, or rockshaft piston packing leaking.

Can't remember if the 4020 had a surge valve or not. It's ball could be not seating properly.

 

[Bob]

The hitch control valves are in a housing atop the RH side of the rockshaft housing. The valve is NOT shown in this drawing, but it would sit on the rectangular area at a slant, in the foreground, with the 8 mounting holes visible.
<img src = "http://jdpc.deere.com/pimages/R819/R819___________UN01JAN94.gif">

The factory shop manual will have detailed instructions as to how to narrow down the problem to a specific component.

WHATEVER you do, don't mess with the valve on your own, DEFINITELY NOT without a factory shop manual "at hand"!

The lift piston is accessable though the cover at the back of the housing, shown to the LEFT of the drawing, There is also a "thermal relief valve" in the piston cover, and they have been know to leak, allowing the lift to settle.

So there you have it.

1.) Possible bad lift piston seals.

2.) Possible control valve porblems.

3.) Possible thermal relief valve problems.

How long IS the lift staying up after shutdown, with significant weight on it?

 

[Anonymous-0]

Well actually here is what I do...T rais it up to any position I have to bring the lever all the way up...then lower it to mid point position. The three point hitch will lower to that point then slowly go down from there...

 

[Anonymous-0]

Well I have a 1500 lb cutter and it falls from the top in about 5 min after shut off, but when I crank it up it goes right back up quickly to the top...that is if the lever is at the top.

 

[Anonymous-0]

Bob, how much am I looking to spend to fix this???

 

[Tx Jim]

Raletgh, Bob and the others have given you some good ideas. I suggest that you go through the L&amp;D adjustments exactly as described in the John Deere technical manual as I've seen linkages way out of adjustment before cause problems. Jim