International 3120 Backhoe

[RobertoV]

Problem with a 1962 (give or take) International backhoe 3120. Backhoe arm will stop moving from left to right after 30 minutes of use. Any suggestions/ideas would be appreciated.

 

[Harold H]

If youare saying it slowly drifts left or right when you want it stable, either your steering cylinders are leaking by or your control valve is leaking by. Just replace o-rings and saeals in cylinders and control valve. If it is moving under power when you don;t want it to swing, your contol vale has a extreme worn internal condition and detents. The control valve will need a complete rebuild.

Harold H

 

[bc]

I just got an old IH tractor with backhoe. I've been fighting hydraulic issues but with the steering and the hoe has been ok for what little I've used it.

Some more info would help. Are you starting this up in the freezing cold and then the hoe and boom will move left and right for the first 30 minutes until it warms up? Or is the fluid already warmed up but only allows you to move the hoe back and forth for 30 minutes? Also does the boom, dipper, and bucket still work? I want to say some type of bypass issue where it plugs open but that depends. Do you have milky fluid indicating water and therefore possible ice in the system? Maybe something plugged the filter? Is the power steering and front end loader, etc. working? Have you used the hoe much?

Anyway, Harold has already helped me. I have a leaky left side cylinder and if I leave it sitting with the bucket off the ground, it will eventually move over to the left a little. It may wait a while till the summer because it looks like it would be a bear to remove that cylinder to R&R it. It isn't a problem when I'm running around moving bales.

 

[Darren in Pesotum]

I know of a place that can supposedly rebuild a backhoe control valve for around $200. If you are interested, let me know and will find the info. You would have to pay shipping of course.

Darren

 

[RobertoV]

Living in South Texas the weather is always hot, usually 80+ degree. The arm, boom and hoe will work beautifully for the first 30 minutes or so and once the tractor warms up, the arm will no longer move left to right. The boom & hoe continue to move without a problem. Everything else works fine, power steering, loader, etc. No milky fluid indicating water.

thanks.

 

[RobertoV]

Living in South Texas the weather is always hot, usually 80+ degree. The arm, boom and hoe will work beautifully for the first 30 minutes or so and once the tractor warms up, the arm will no longer move left to right. The boom & hoe continue to move without a problem. Everything else works fine, power steering, loader, etc. No milky fluid indicating water.

thanks.

 

[bc]

Well that isolates it to the swing cylinders and control valve. From what I understand, sometimes the spool in the control valve will stick in the center which sounds like a good possibility here. I don't know if it is a very common problem. There is also a check valve/ball and spring in the valve that could be weak or getting gunked up and bypassing. You can pull that out to check it. Look for a little bull plug and if it has a ball and spring don't let them fall out and get lost. I checked one that was sticking down, had a little trouble getting the ball to go in and then push it all the way in although it was more of a space problem getting my hands and fingers in there.

Try tapping on the center part of the control valve while trying to make it swing and see if that unsticks the spool.

You can also take your lines loose one at a time from the valve to see if you have flow when you are supposed to. Try this with the boom swung to one side and then later to the other. You would have to move it while you can and then leave it before it warms up.

The IH 3120 does not show up as a valid model on the parts search for international at www.caseih.com or at the case construction website www.casece.com . Find the model # for the hoe on the hoe name plate and try the construction site. If so you can find a schematic and parts list. Also just put backhoe in the model search category and a number of them will come up. You will find a similar one so you have a picture.

Just guessing, if the spool is sticking in the center, maybe it has a weak seal/orings. Works ok with colder heavier hytran, but once the fluid warms up and thins out, then it leaks by.

Let us know what you find out. I know it is a lot of work to tear into these and take them apart and it is nice to know what is broken before you do.

 

[RobertoV]

Thanks! I will see what we can do to solve the problem and again many thanks.

 

[Anonymous-0]

What model tractor is it on? I have a 3414 industrial with the 3140 hoe. mine uses 2 hyd pumps. the swing and stabilizers run off one and the rest off the front one. you may have a weak pump or relief valve. go to a komatsu dealer and order shop manual GSS-1339,about $25. answers tons of questions. Some parts for it are tough to find. good luck!