SOME TECHNICAL ADVICE!! rockshaft valve removal

[jdauto3720]

hello, so I've had a problem with my rockshaft arms not lifting 3ph. I'm starting to lean towards an issue with the rockshaft control valve, located behind a cover, whether its a linkage became disconnected, a valve is stuck open/closed, or a seal blew, etc. i want to take that cover off and inspect the valve assembly to rule that out. just wanted some advice on removing that, if theres anything i should be careful of if anyone has done this before. some insight would be great. tractor is a 2008 JD 3720 w/2000 hrs. thanks in advance for any info! see attached photo of what I'm talking about.

 

[waycoolmarine]

I have done a couple 4400 and similar should be the same, what I remember is a roll pin in handle to shaft breaks , cause the shaft seizes. it takes about 8 hours of patience and lots of penetrating oil - no heat- repeat no heat- soak the shaft then soft mallet and punches and lots of penetrant work shaft back and forth, takes hours be gentle and soak , there is nothing under that cover to be afraid of . look for the roll pin at base of handle. this has been discussed before you should be able to find old threads. as much as you want to hurry and use heat remember no heat

 

[jdauto3720]

okay so you believe its the shaft/linkage that connects to the valve via a roll pin that might be the possible cause. i will hide the torches before i begin.
ill search through the threads, wasn't able to find anything before.
thanks

 

[joecdeere]

shoot me your email, I have a PDF of the tech manual you're welcome to, might provide some insight

Joe

 

[jenkinsph]

I remember having similar issues with my 4520 (2009) and had to remove the rockshaft cover. Found a linkage had come loose, put it back together and tightened everything up. It was an easy fix as I recall and waiting for the new sealant to dry took up the most time. The top casting is light enough for one person to lift and recommend you have a clean piece of plywood or similar to set the cover on when removed. No problems since then either.

 

[jdauto3720]

okay, so it was the top cover your removed not the cover on the left side that encases the valve?
thanks for the help

I remember having similar issues with my 4520 (2009) and had to remove the rockshaft cover. Found a linkage had come loose, put it back together and tightened everything up. It was an easy fix as I recall and waiting for the new sealant to dry took up the most time. The top casting is light enough for one person to lift and recommend you have a clean piece of plywood or similar to set the cover on when removed. No problems since then either.

 

[waycoolmarine]

I would remove the seat and the side cover before removing the whole assembly. that will allow you to see when you move the handle if its just broken pin [ common ] or linkage are something else.

 

[jdauto3720]

ya I've been tracing everything back to were it enters in the valve assembly, everything is working up until that point. i would rather try the easier stuff first before i get into tearing something big/complicated apart. My tractor has a cab/ suspension seat. do you know if its a big job to remove the seat on those? thanks

 

[jdauto3720]

so i removed the rockshaft control valve cover and everything was as it's suppose to be. when you push the lever the linkages move and push the valve in. i removed the valve and pushed in by hand i can see the valve moving and nothing clogged or blocked. Any ideas what else could be the culprit? possibly something to do with the piston that operates the lifting action? if the fluid is making it to that point i can't see it being much else.

 

[waycoolmarine]

a dumb question is the roll pin broke and not moving the valve when there is pressure? is there a inline filter about 1-11/2 inches around and 5 inches long could be clogged. almost always its something easy and stupid.

 

[jdauto3720]

not exactly sure what you mean by roll pin, however here is a picture of the control valve, when i move the lift lever, all the linkages move and push the valve and compress that spring in the picture. is the 'roll pin' before the valve in sequence(if the pin was broken would the valve not move).
Also so the filter your talking about, is that the in-line hydraulic suction filter? i did remove that and cleaned it out with brake cleaner. unless theres another in-line filter for the rockshaft?
i hope its something stupid that I'm missing, optimism is slipping tho.

 

[waycoolmarine]

the roll pin that goes bad , is where the handle mounts to the shaft that runs under the seat across the tractor . that shaft gets tight and you end up breaking the pin. it will move by friction/ tight fit but that shaft has to line up with the holes in the handle other wise the valve is not in correct alignment the tractor should start you may have to jump seat switch , I do not think there is oil pressure there. you could then operate valve manually if there is oil pressure on the valve the handle may not open the valve it might just slide when you move the handle . and the filter is on a oil tube that runs on top of 3 point

 

[jdauto3720]

On my tractor the handle connects to a cable, which rotates the shaft going under the seat area. The handle itself doesn't move the shaft, but the movement of the cable that makes the action. The tractor starts fine and everything else works. I'll have to have another look for that filter, but I couldn't see anything. I can't find anything on any diagrams either other than the trans filter and in-line hydraulic filter.
I appreciate your help in this!

the roll pin that goes bad , is where the handle mounts to the shaft that runs under the seat across the tractor . that shaft gets tight and you end up breaking the pin. it will move by friction/ tight fit but that shaft has to line up with the holes in the handle other wise the valve is not in correct alignment the tractor should start you may have to jump seat switch , I do not think there is oil pressure there. you could then operate valve manually if there is oil pressure on the valve the handle may not open the valve it might just slide when you move the handle . and the filter is on a oil tube that runs on top of 3 point

 

[jdauto3720]

Waycoolmarine, you were right. Inside the fitting feeding the rockshaft valve, I found a screen that filters the hydraulic fluid. The filter was dirty, however the was a hole busted through it. So I don't think that it is restricting the flow. But would it be possible or likely that maybe something went through and jammed up a channel? Or maybe by having a small hole in the filter does that mess something else up. I'll post a picture what I'm taking about.
Thanks, let me know your opinion. Picture was with a camera inspection tool.

 

[waycoolmarine]

I would get a new filter , if you can get the screen out look and see if it looks missing pieces maybe follow oil line and I don't remember exactly ,but it goes to the valve remove the vale and look for the piece light air pressure with air hose that screen was probably clogged for a while till the pressure broke it and the gunk on the filter is probably on back side of valve the valve is the smallest point to jam up if I remember some of those cartridge filters are also a check valve could be caught there

 

[jdauto3720]

Yes I agree with you completely, i wouldn't re-install that fitting with the broken screen. I ordered a new one today and should be in tomorrow. I will pull the rockshaft valve cover back off again, and pull the valve.. I'll inspect each port to make sure there are no obstructions and use very light air pressure to clear channels. I noticed when I first took the valve off, some of the fluid that was in there was still the same color as the old oil I drained(greyish). even after running the tractor for an hour or so after changing the fluid, it's as if the fluid was not able to make it to the valve and mix in for a similar color fluid throughout. Which leads me to believe maybe there is an obstruction and the new fluid is not making it throughout the valve assembly. I feel like the end is so close! Fingers crossed.
Thanks

I would get a new filter , if you can get the screen out look and see if it looks missing pieces maybe follow oil line and I don't remember exactly ,but it goes to the valve remove the vale and look for the piece light air pressure with air hose that screen was probably clogged for a while till the pressure broke it and the gunk on the filter is probably on back side of valve the valve is the smallest point to jam up if I remember some of those cartridge filters are also a check valve could be caught there

 

[waycoolmarine]

another thought do you have power beyond check the quick connects they have small passages , and must be hooked up for 3 point to work. quick connects some times go bad or plug ,or just pop part way off good luck my friend and keep us posted

 

[jdauto3720]

GREAT NEWS! finally the lift arms are operating normally! i replaced that in-line screen filter with a new one, which after seeing the new one, realized how bad the old one was. maybe where the old filter blew through, it wasn't keeping the pressure in check. I'm not 100% exactly sure thats what it was, but after putting everything back together, it now works. I'm so relieved as i had scheduled john deere technician to make a service call tmrw @ $100/ per hour! was i ever happy to call up and cancel that! I must thank everyone for the awesome help and information in helping me fix the issue!
Thanks again!!!

another thought do you have power beyond check the quick connects they have small passages , and must be hooked up for 3 point to work. quick connects some times go bad or plug ,or just pop part way off good luck my friend and keep us posted

 

[Tx Jim]

jdauto3720
Congratulations on your success.
You just reaffirmed what I was taught back when I was employed by a JD dealer back in the 70's-80's to "do the easiest things 1st" which normally includes changing filter &/or sump screen.

 

[jdauto3720]

thanks jim, i was lucky it was something easy!

jdauto3720
Congratulations on your success.
You just reaffirmed what I was taught back when I was employed by a JD dealer back in the 70's-80's to "do the easiest things 1st" which normally includes changing filter &/or sump screen.