John Deere 4300 3 Point Malfunction

[sloch24]

My 3 point just recently started screwing up (more than usual).

Since I've owned the tractor (2016) when I raise it all the way up the motor would labor, so I would have to move the lever down a bit to get it to stop.

The other day, the 3 point started dropping all by itself. It was very annoying dragging my box scraper while trying to move stone with the bucket.

Upon further inspection, I noticed that when I move the rock shaft lever, the 3 point doesn't move at all until it hits a point about 3/4" back. At that time, it acts as a "all the way up" lever. The 3 point then lifts all the way up and the engine labors until I move it down slightly.

At this time, moving the lever down slightly seems to hold the level steady until it doesn't. I can't trust it to stay up, and while I'm running the tractor the 3 point gradually lowers until I'm dragging it.

With the 3 point fully raised, if I move the rock shaft lever down just slightly past the "neutral" position, the implement lowers all the way to the ground.

Basically what I have now is an all raised or all lowered situation.

I pulled the seat and am looking at tearing apart the left side rear fender to take the cover off the valve and check for debris in the valve such as screen material that may have blown past the inline filter (I haven't pulled that line yet, but that will be the first thing I do).

Any thoughts? Am I on the right path? Does it sound like something is caught in the valve, or am I barking up the wrong tree?

Any help is greatly appreciated!

 

[beenthere]

when I raise it all the way up the motor would labor, so I would have to move the lever down a bit to get it to stop.

That would be the adjustment to the feedback arm/lever on the left side somewhat under the seat. Tells the internal valve that the arms are at the top, need not go further.
Whether that being out of adjustment caused further internal valve problems, I do not know.

Your thought on that screen being the problem may be the right path. When that was first reported to be a potential problem, I changed out that original screen arrangement so avoided the problem of the screen blowing out and into the valves.

 

[sloch24]

That would be the adjustment to the feedback arm/lever on the left side somewhat under the seat. Tells the internal valve that the arms are at the top, need not go further.
Whether that being out of adjustment caused further internal valve problems, I do not know.

Well, I never intentionally let it labor, but when at higher throttle, it could have and I didn't notice it i suppose.

Is that the adjustment at the rear of the tractor that sets the arm height? I see that linkage on the rock shaft, but I didn't notice anything going to a valve. It looked more like a positive stop. Maybe I need to look closer.

 

[beenthere]

This is the adjustment rod.. key # 8 that shuts off the lift valve.

 

[sloch24]

Wow! That's a great diagram! Can I ask where you got it? Is it part of a service manual?

The only manual I have is the operators manual and it doesn't show any of this. I'd love to get my hands on something a little more in depth.

Now I have a few things that I can check out. I assumed that maybe one of those "bolts" were check valves, or relief valves, but I had no way of knowing until now.

Thanks!

 

[beenthere]

That pic came from the service tech manual.. should also show in the jdparts but I couldn't put my finger on it there.

https://partscatalog.deere.com/jdrc/navigation/equipment/75863

 

[Wagtail]

This is the adjustment rod.. key # 8 that shuts off the lift valve.

Good onya beenthere.

I read threads like this (all colours too) to learn how my tractor works and to spot/analyse potential problems/faults. I didn't know about the adjustment rod... my 3PH simply comes up and stops by 'magic'. :wizard: Now I know better.

 

[waycoolmarine]

look at the parts diagram if i were a betting man and i am roll pin #40 is broken and linkages is -tight- from age use penatrating oil and loosen up the linkage , its not in the adjustment linkage you do not have to remove the fender - just the seat and surrounding metal and plastic

 

[super55]

Almost 100% the one of the nuts backed off on the threaded rod causing too much play in the linkage. My 4400 used to do the same exact thing and it was a loosened nut.

 

[sloch24]

Well, I spent last evening tearing down everything and here's what I found:

@waycoolmarine - 100% correct. That roll pin was broken and the shaft is seized. I hit it with PB Blaster and then removed the linkage in order to remove the broken roll pin.

@super55 - Also correct, but in this case, there is a deeper problem.

So, here's what I did in order:

1) Removed the input hydraulic line in order to inspect the inline filter. It was blown through, but very little if any pieces were missing. I removed the filter basket from the fitting and re-installed. (Should I do something about this after I get it running, or just run it without the filter?

2) I found the adjustment linkage for the 3 point that stops it from going up any further. As previously stated, I removed it, removed the broken roll pin, and saturated the shaft in penetrating oil in an attempt to free the shaft. No dice as of yet.

3) I removed the wheel & fender, and took the emergency brake off of the bracket in order to get to the hydraulic valve. I removed the cover, drained the residual oil out of it, then removed the valve and removed just about everything that could be removed (one at a time) to check for debris that might be causing me a problem.

At this point I'm nearly certain that my problem lies in this valve, but I see nothing wrong with it. Can these be rebuilt? Is there anything I can do with it?

It's acting as an on/off valve instead of a variable position valve. It's all or nothing, and I don't see how any other component could be causing this.

So, right now, the tractor is torn apart and the valve is removed and reassembled on the bench.

Suggestions? Where to go next? Is this valve still available if it can't be repaired? Cost?

I appreciate everyone's help so far. I'd like to get this figured out so I can use my tractor again!!!

The valve does have a name and numbers on it:

418B
Danfoss Fluid Power
Easley, SC (USA)
AM119160

*I haven't looked up the valve at JD-Parts yet to get a number. I'll be doing that here shortly.