L2250 Air in Hydraulics

[fjace]

I have a Kubota L2250 with a LA400 loader. The unit has low hours 275 but was sitting for 3 years before I bought it. I replaced oil, filters, everything I felt needed replaced or changed when I first got it 5 months ago. The tractor has been working fine no issues until about two weeks ago. The power steering started to make noise when you went from side to side and became sluggish after using the tractor for a few hours. I also noticed the loader becoming sluggish. The hydraulic fluid also looked milky. I replace the hydraulic fluid thinking maybe it was contaminated or something even though it was replaced 5 months ago. No change. The more you use it, it shutters and does not want to function. Increasing the RPMs make the problem worse. When cold the hydraulic system works good in idle, but makes noise when not under load. Could this be the relief valve?

So I have come to the conclusion - air in the hydraulic system. I have tried bleeding any air that might have been caught in the loader cylinders by going through all motions and I have also let the unit idle for a while, but nothing has changed. My next step is to look for suction leaks and also maybe the relief valve? Does anyone have schematics on the valve block?

Any help at all or ideas would be welcomed....Thanks

 

[Bulldog]

First thing I would do is trace the hyd pump input line back toward the rear of the tractor. In most cases around the front of the right side floor board there will be a rubber hose on the metal line. It's pretty common for these to split (almost every time on the inside) and they won't leak fluid out, just air in. Check that and see if it's the problem.

 

[fjace]

Well I replaced the hose between the two metal pipes - Hydraulic intake line and no change. If anything it is worse now than before. I seem have lost what little power steering I had. I then went ahead and replaced the return line from the power steering box to the filter base and again no change. What I am noticing now is that the pump surges like it is building up pressure. As I use the loader it goes up an inch, stops, you here the pump surge again, goes up another inch...etc...

I am going to remove the filter next and check to see if it is not making a good seal or something is wrong. My next step after that would be the pump or the valve block.

Would a bad pump create air in the system? The tractor has power steering so the hydraulic pump has a piggy back pump behind it, could this pump be bad causing the issues. How about the valve block?

 

[Browncamp]

I have the same tractor and recently encountered the same problem . Didnt replace the rubber coupling yet . Does anyone know what the problem ended up being ?