3320 Rockshaft adjustment

[Millalien]

Couple of problems with my rockshaft arms on a 3320 - one is that the original functionality of setting the rockshaft height with the rockshaft control lever is totally gone - it used to be that setting lever to 1 set the height to whatever, setting the lever to 2 would be higher than 1, setting to 3 ... and so on, but I could leave the lever at the index number and the RSA would stay fixed at that height. It was handy and was also a selling point, IIRC. Anyway, what I have to do now is fully engage to the lever to raise the arms (e.g., position 6), and then back-off the control lever just enough to stop the lift when it gets the height I want - kind of like its now a three position lever: up, back-off to stop, and down. Probably related is that if I don't back of the control level, the RSA goes into bypass relief.

There's a rock shaft height limit adjustment that I think will solve the bypass relief problem - don't know how to do that - and I've been hunting around for the service procedure to adjust that and the height indexing thing without any luck. I'll really appreciate anyone who can point me in the right direction.Thanks in advance...

 

[beenthere]

The service tech manual for the 3320 should have that info, and a copy would be handy for you to have.
From your description, if I read it close to correct, it does sound like something has come loose or is broken.

But check the "rate-of-drop" valve that controls the hydraulic flow to the rockshaft piston, just to be sure that it isn't part of the problem.

 

[Pipestone Kid]

I don't know about the 3320, but I have a 4110 with the same problem. I have the service manual for my tractor and I have tried every adjustment there is and to no avail. I had my mechanic friend help and we have come to the conclusion that the problem is internal. The diagrams in the manual show a pin inside that we think is partially sheared. Don't know for sure and as long as it doesn't get any worse, I am not going to find out.

 

[swines]

Flip the seat forward so you have better access and then go to the rear of the tractor. As you're facing the rear of the tractor, look on the left side at about the 7:00 o'clock position off of the left rear corner of the seat platform. You're looking for the rockshaft feedback control rod - it will be to the left of the rockshaft.

You will see a small control rod it will be the only one at the left rear of the tractor - that is the rockshaft feedback control rod. It's fairly simple to adjust, you just make it longer or shorter and that is what controls how high the rockshaft will lift. You just have to play around with it to get the correct length. It doesn't take a whole lot of adjustment, so only screw it in or out 2-3 threads at a time.

It's dead nuts simple to do - you can't screw it up. If the rod is too long, it will lift too high and go into overload, if it's too short it won't lift high enough. You have to play around with it until you get it "just right."

Make sure the tractor is warmed up and the hydraulic fluid is warm. You'll have to test it with the RPM advanced to at least 1200 so the flow rate through the system is high enough. If you adjust it with the tractor idling, you'll find out that the lift is not as high as it is when you have the engine at a higher RPM.

If the RPM is too low, you'll adjust it and it will be "perfect," and then when you have the tractor at a higher RPM you'll find it will lift too high and go into overload.

Getting at the locknut on the rod is a PITA. I finally went to Sears and bought a 17mm Craftsman open end wrench and cut it off to make an extremely short wrench. Then I shaped and rounded the sides of the wrench to make it smaller so that it fits into the small space better.

You also may want to check the setting on the rate-of-drop / lock control valve which is a knob that is near the heel of your right foot when you're sitting on the seat. If you inadvertently hit that with your foot, you may have accidently rotated it further closed.

 

[beenthere]

And I believe the adjustment is to be made with a load (like ballast) on the 3 ph at the time to get it right. IIRC

 

[Bavarian]

Are you sure that your system is out of alignment? There are some posts on TBN about the same issues. Most of them on 4x00 series. Most of them found a broken shearpin.

 

[swines]

Are you sure that your system is out of alignment? There are some posts on TBN about the same issues. Most of them on 4x00 series. Most of them found a broken shearpin.

There is no "alignment" - there is a calibration of the lift height through the feedback control rod.

The OP's original post said -

Probably related is that if I don't back of the control level, the RSA goes into bypass relief.

This means it's lifting too high. Checking the feedback control rod for calibration is simple to do and needs to be eliminated as the problem BEFORE you start looking for more complicated problems.

You know, standard trouble shooting procedures, you check all of the obvious easy things first before you dive into the complicated ones?

That is how YOU do it isn't it?

 

[Kyle_in_Tex]

Here's a link to my 4310 rockshaft fix

Maybe it can help you out.
http://www.tractorbynet.com/forums/john-deere-owning-operating/345513-4310-rockshaft-repair-filter-replacement.html

 

[beenthere]

Millalien isn't offering a reply to the help he has received. Maybe fixed, maybe not.

 

[sunnyside360]

Millalien isn't offering a reply to the help he has received. Maybe fixed, maybe not.

Don't you love it when that happens!!

 

[Millalien]

Don't you love it when that happens!!

Yeah, sorry, we got wacked with wicked bad weather and a ton of work, so I drifted off this problem for a bit, plus was waiting for the service manual to come in which I ordered as per one suggestion. Manual showed up yesterday and I'm back to it.

I think the lift arm position linkage is fubar and needs to be set back to spec, but the service manual only says what to do (e.g., "adjust linkage."), not how to do it (e.g., "adjust linkage by..."). Swines above explains how, and I'll give that a shot this weekend now that things have settled down a bit.

I really appreciate all the replies and beg pardon for not being responsive to my own thread !!

 

[sunnyside360]

I have adjusted my rockshaft (3PH lower arms) to raise higher to connect the backhoe and have to agree that SWINES description above is excellent and superior to the manual IMO.

 

[Millalien]

No luck adjusting the feedback control rod - we had to toolsmith a wrench to reach the rear locknut and traveled the adjustment all the way up and down the thread -- no change in the lift height.

 

[sunnyside360]

No luck adjusting the feedback control rod - we had to toolsmith a wrench to reach the rear locknut and traveled the adjustment all the way up and down the thread -- no change in the lift height.

Definitely something wrong there. I adjusted the rod on mine a full 2 turns which caused the relief valve to actuate when the 3PT lever was pulled all the way back. Then backed it off 1.5 turns to get the 485 backhoe raised enough to connect/disconnect. End result was that it only had to be adjusted 1/2 turn from original setting.

Hopefully someone with better knowledge will chime in and help locate the problem.