3 PT Lift Arms Acting Up

[zrider350]

I have a 1996 L2350. Only had her a few months and over that period their performance has degraded to the point now where it is unusable. I had a PTO shaft issue so I needed to replace it and I figured since I was in there I would replace my hydraulic fluid screen in hopes that would improve the performance but it is actually worse now.

When I first crank it up I can lift my 5 foot brush hog. I can even do a little work with it but after I drop it a few times it gives out and will not raise any. As if there isn't enough pressure. I removed the brush hog to see if the arms would lift themselves and if I raise the RPM's they will crawl to a lift without any weight on them.

Typically after it rests to a cool down phase (several hours) she cranks back up and the arms lift strong again. I was thinking it was a combination of air in the lines and a dirty screen before that was causing this performance but since I put the new fluid and the screen in there I can only drop the brush hog a few times before it will not lift it again. Another thing I notice without anything connected to it is that when I lift the arms they lift ok and once the RPM's lower they drop a little. Raise the RPM's and they lift a little more and let off and they drop. This makes me think that there is some kind of pressure issue.

My two thoughts are pressure relief valve and/or the pump itself. Any ideas on where I can check so I can keep from taking this back to the shop? I have also monkey with the valve under the seat that controls the speed the implement drops and that appears to function ok. I notice once I tighten all the way where it wont drop any longer I have to back off quite a bit to get it to drop again.

I am just trying to give you guys as much info as possible to help diagnose. I appreciate your help in advance.

Thanks,
Chuck

 

[Bulldog]

You already took care of the first suggestion by changing the fluid and filter screen. You said that it had air in the lines before the service. Just changing the oil didn't stop the air trouble. If you had air in the system before then you have it now unless you made other repairs. How or why did it have air in the system? This could be the root of your problem.

 

[zrider350]

I appreciate the response Bulldog. I have not confirmed air in the system but assumed that was the case based on what I have learned about how the hydraulic system functions and the behavior. I am clearing my land with the tractor and there is quite a bit of contour on the land and Kubota told me that I probably got some air in the line and I needed to work the lift arms to get it out. Is there a way to bleed the system of any potential air? I changed my engine oil and flushed the radiator fluid real well because somehow it go overfilled with oil and was leaking out of the overflow. I regularly check my fluids and never noticed too much oil but when I got it back from Kubota there seemed to be about an extra gallon of oil in the engine. I am sure it was always there, why would they overfill with oil. After changing the oil and filter the hydraulics seemed stronger but that could be in my head. While I was flushing the radiator out I had to continually start and stop the tractor to flush the system and so I used that as an opportunity to play with those arms and study their behavior. I picked my brushhog back up Monday and played with the arms on the trailer and they functioned ok. I still think there is an issue. As soon as I run it for about 20 minutes or so with the PTO engaged is when it seems to poop out. Then I have to wait a few hours for it to go cold before they work again.

 

[Bulldog]

Hi zrider350, welcome to OTT by the way.

I went back and reread your first post and noticed your only had the tractor a short while. Going by that I assume you don't know much about the history of the tractor. Some hyd oil is not made to go in just any system. If the former owner changed the oil and installed the wrong oil in it may have been foaming therefore it would have air in the entire system. I hope you didn't make the same mistake and used a quality hydrolic/transmission oil (such as Super UDT) when you changed it for yourself. I use a full synthetic oil in all my tractors but wouldn't want to dump it in one that I didn't know much about just due to the expence.

As far as the air in the system goes, it should remove itself by working the lift arms in normal operation as long as there is no other problem.

On the over filled engine oil. Who worked on your tractor at the dealer? You don't have any way of knowing unless you were with it the entire time it was there. It could have been several people working on yours and one thought it was low and put oil in and the other guy knew it was low so he out oil in and so on and so forth. Myself, I prefer to do my own service work that way when it's not correct I know exactly who to blame, Me. The less hands involved the better. Hopefully this was a fluke and you don't have bigger issues with the engine.

I don't see how the grade of your land would cause you to have problems with air getting in the system. I work mine on some grades that require 4WD just to operate there and don't have any trouble at all.

Keep us posted on how it does and maybe now you can just run it with no more trouble.

 

[zrider350]

You are correct Bulldog regarding the history of the tractor. I don't know much about it outside of what the previous owner told me. When I initially started having issues I put in a little UDT (the stuff Kubota sells) as they told me I had to use the detergent free fluid and I thought the level could be low. This was before I noticed they painted over my site glass to determine the fluid level. I had the tractor serviced because I couldn't get my PTO shaft off that I bent so I brought it to Kubota. They replaced the fluid so I am assuming they used the right stuff since they are a Kubota dealer and they are the ones that recommended that I use UDT so I don't think it would be getting air from there. I actually don't think that air in the lines is the issue so I was wondering if someone has another suggestion. I read on another forum about a guy not being able to pick up a bale of hay with his lift arms with my same tractor and he tested the pressure and wasn't getting enough. He somehow shimmed the pressure relief valve and got the pressure to increase and that fixed the issue. I was wondering if I have some kind of pressure leak or potentially am not getting enough pressure. What sucks is the lack of consistency. On a fresh start the hydraulics are strong and after running for a short while they quit working completely.

The reason I mentioned the oil was I thought that could have something to do with it. After changing the oil and flushing the radiator the hydraulics seemed to function faster than ever or maybe that is my imagination. I have yet to run it in the field since then though so I will try that out this weekend.

One thing I would like to know is should my arms drop a little bit when the rpm's drop. I noticed this when I was testing. I haven't noticed this under a load but if there is no load on the arms and I raise them they go up and if I give it rpm's they go up a little higher. Then if I let it die down to an idle the arms drop a couple inches. I would not think this behavior is normal but I am new to tractors.

 

[HighwayRanger]

I previously owned a B8200 and had the exact same problem twice over a fifteen year period The problem started after the tractor started too warm up. Both times it was caused by water in the hydraulic fluid which caused foaming of the UDT fluid If you pull the dip stick after running the tractor and hydraulics up and down, see if the fluid appears to be foaming. You will see lots of little bubbles as opposed to clear fluid. Drain and replace with a good high quality UDT fluid.

Hope this helps you.

Sent from my SAMSUNG-SM-N900A using Tapatalk