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.