Hydraulic pressure YM2000BD

[FL_Jerry]

I have an issue where if I have a load on the 3pt, the system is pressurized. In the case of my brush cutter, around 1300 psi. If I lower it slightly, the pressure goes to about 0 and slowly climbs back to 1300. The pressure seems to follow the load weight, the lighter the load, the less pressure.

The 3pt control has been replaced. The load doesn't go down when you shut the tractor off, well eventually after several days. The maint valve when shut, keeps the level for at least a week.

The hydraulic system gets hot and eventually won't raise much of a load till you let it sit for a while if operated with the load. If I'm doing loader work, I raise the 3pt, close the maint valve, and then lower the 3pt control valve. The pressure goes to 0 and only raises when actively using the loader valve, after which it goes back to 0.

Bypassing the loader valve has no effect.

The symptoms kind of made me think the load is always needing new fluid to maintain position, but shutting the tractor off doesn't cause the load to fall.

Any ideas?

 

[284 International]

Where are you measuring the hydraulic pressure? The portion of the fluid from the lift cylinder to the valve will always be under pressure when a load is applied: That pressure is what holds the lift up.

The only thing that sounds like trouble is that you mention it takes some time after being warmed up to lift a load. Are you sure that it's because of the system being hot? Might it be a plugged suction filter, or an air leak somehow?

 

[FL_Jerry]

I have a guage T'd in between the pump and before any valves.

All the usual stuff such as screen cleaning and replacing the rubber coupling pieces on the suction side have been done.

Am I sure this isn't normal? No, I didn't know there was an issue till I put the guage in, which was something I did after replacing the pump. The pump was replaced because it got to where the old one wouldn't raise anything hardly even cold.

I was hoping someone with a 2000 or smaller model with the same 3pt control valve has a guage in line to compare.

 

[winston1]

Mine is a 2002 and I don't have a gauge but I think most all models should not have a constant 1300# before the 3 point valve. After it, probably so. I know you stated you got a new valve but something sounds amiss to me. Was it doing this same thing before the new valve?

 

[FL_Jerry]

Yes, the old valve did pretty much the same.

Thanks

 

[winston1]

One more stupid question. If you let the load 1/2 way down will it hold and do the same thing?

 

[FL_Jerry]

I want to say yes, but I'll try it this week end and see for sure.

 

[FL_Jerry]

It leaked down when the 3pt is less than or equal to halfway.

 

[winston1]

Seems to me like the problem has to be in the 3 point control valve. I know you changed it. Certainly not confident in what I am saying. Just don't see what else could cause your system to have to maintain that constant pressure. Where are the hydraulic gurus??