JD 4200 hydraulic leak??

[Egon]

Get some oil on those linkages and find out how loose they are before you get too excited.:thumbsup:

Is the drop more noticeable at lower rpm's?

 

[kennyd]

Your tractor comes with a 1-spool or 3-spool monoblock valve attached to
the main gearbox's right upper side. Normally, hydraulic pressure to operate
your valves goes from your implement pump to your factory valve(s), and
then from that valve's PB port to the 3-pt cyl valve. If you add an
aftermkt valve, it must be plumbed in series with the other valves, or get
its hyd power from a diverter. Since your Danfoss valve does not use
its PB port, it should be plumbed off a diverter. If it is not, its OUT
port (which is not designed to handle high pressure) may be plumbed to
the IN port of the SCV(s) or the 3-pt, which is not correct.

Something does not seem right here.

I agree, but think the hookup is what's causing his leakdown problem.

 

[Willl]

It does work until the pressure is equalized.

How much movement do you think that would take ? 1/2" ?

 

[duksrule]

Not sure about how it is plumbed but when I got the tractor it worked great, and the bucket held wherever you left it for however long you left it. It leaks off pretty fast and like I said if you don't stay on top of bumping the lever it will actually leak enough to dump the bucket on you.

I would think that if it came with a factory spool valve that they would have used it rather than adding one. I guess I need to get under there and see exactly what is going on. I am thinking from what you have all said that it is the control valve for the loader that is going bad. I haven't exactly been easy on it over the years and the leak off has gotten worse over time. It is bad enough now that I want to fix it though. Maybe my goal for tomorrow will be to disconnect the QDs and see what happens to the bucket when I back up.

 

[kennyd]

How much movement do you think that would take ? 1/2" ?

Why don't you offer the OP some help instead of challenging me then since you know it all?

 

[Willl]

Sorry dude, not a challenge, just trying to learn cause I'm quite far from knowing it all.

 

[Willl]

I was thinking that if he did set it up the way I quoted you, that if he removed the non-rod side fitting and if the piston seal did leak past, it would continue to fall ?

EDIT; Oops, my bad. I meant rod end.

 

[dfkrug]

I agree, but think the hookup is what's causing his leakdown problem.

One of my points is I do not understand how the OP's system is hooked
up. If it is not hooked up correctly, perhaps that could cause his drift.
My money is on the valve's load checks or the spool not moving
completely to the center position.

Since the OP reports no external leaks, removing the hoses with the
FEL boom in the air as you describe will not show him anything useful.
Only an external leak can allow the boom to drop in that case. Otherwise,
the retraction of the cylinder will attempt to compress the total volume
of trapped fluid and it will have no place to go. This is true even if
the piston had completely disintegrated.

 

[duksrule]

OK, so I did what Kenny said. The bucket stayed up like it was hung there on a hook when I disconnected the QDs. So then I hooked it all back up and started looking at the valve. I took the hex caps off and found a spring and a piece of black plastic on both spools. The black plastic is a tub shaped thing about a half inch long. One side (tilt side which leaked the most) was mushroomed pretty bad and the other side you could see that it was deformed. I took the plastic tubes out and flipped them over then cleaned up that damaged part. Put it all back together and the leak down is much much less. I put the bucket all the way up and shut down the tractor. It stayed up there for over a half hour. So that is MUCH better and a part of me says it is good enough but if I could find the parts I would go ahead and fix it right. Any idea where to get those little black tubes that go in there under the springs? I also need the rod ends (see pictures at begining of thread) that connect the joystick to the vavle. Or would it be about the same and easier to just change out the valve?

 

[dfkrug]

I also need the rod ends (see pictures at begining of thread) that connect the joystick to the vavle.

You can also find new heim joints at SurplusCenter and they are not
expensive. Even the ones from JD for the factory SCVs are quite
reasonable.

As for your bad load check valves, the worn part is going to be
vendor-specific. You can go to a Danfoss distributor and buy them
if you give the valve part number. Time to do a bit of research.