B6000 Kubota front PTO

[Lodur]

On my Brantly FEL I had an old AICO that didnｴt like. So I got a new with float and it seems to work really nice. There is also a connector where I can hook up i pressure gauge. I have set the pressure to 11,7 MPa
This is how it looks:

 

[KubotaSam]

Another thing.....the screw cap to the fluid reservoir.....after filling the "towers" which double as fluid reservoirs, and cylcling this thing through a bunch of times, I noticed that a bit of air pressure would build up.....i.e. if I removed the cap while running the tractor, it would release a puff of air. Is this right? Shouldn't the dead air space on top of the fluid, in the reservoir be pretty much ambient pressure?

I checked the suction line.....all fittings seem tight...is there a way to tell if air is being let in?

The fluid reservoir defiantly needs to breathe. Get a vented pipe plug or some other sort of breather cap
.Vented Pipe Plug - 1/2" Pipe Thread - Buyers PPV8

 

[J_J]

Here are some vent filters from Prince.

I would select the one where the hole is on the bottom of the nut to keep water out.

http://www.princehyd.com/Portals/0/products/accessories/catalog/PinsGuagesCouplersEtc.pdf

http://baileynet.com/hydraulics/bailey_hydraulics_other_products/?productcategory=1000026

 

[boxer246]

Awesome....thanks fellas for all the replies and excellent info. I think for now until I get the proper breather cap, I'll just drill the pipe plug to get me by.

JJ, or anyone for that matter, explain to me like I'm a 2 year old what is the difference between an open center and closed center valve? I noticed both types as I was browsing for a loader valve setup, and they even offer some sort of plug to convert one type to the other. I tried looking it up and still dont really understand it. Which type do I need for this loader?

Thanks again everyone this has been a learning experience for me. I'm into old motorcycles and cars and can do anything regarding mechanics and some fab.....but hydraulics are new to me.

 

[J_J]

An open center hyd system allows the pump to run all the time pumping fluid through all the valves and back to tank. Pressure is developed when the cyl or motor is using the fluid. With all valves in neutral, fluid is flowing, but very little pressure is generated.

A closed center hyd system is used on some tractors and supply's fluid to the valve ready to work. The only time fluid is flowing through the valve is when the valve is controlling a cyl or motor.

On the vent plug, make sure the hole is down so rain water will not enter. What I would do is, install a 90 degree fitting and then add the filtered fitting so the filter is pointed down..

 

[boxer246]

Ha! So I screwed myself until I get the new loader valve. I decided to take the valve apart to see if there was anything I could replace, clean etc to maybe get this old AICO working better...when I disconnected the outlet fittings the hyd oil came out spitting and foamy white....so obviously lots of air in the system. I took the AICO apart, it was pretty simple....really didnt do anything to it because some of it I couldn't figure out how to get it apart. But it all looked OK inside, put it back together, put it on and also drilled a couple holes in my pipe plug filler caps for venting. Well the loader basically doesn't hardly work at all now! I spits out foamy oil out of my breather hole on the right side reservoir, just wont build up any pressure anymore. I musta messed something up, cant imagine what. SO tomorrow I'll order a new valve and see if that makes it work. I noticed the shaft seal on my Hyd pump is seeping....that shouldn't suck too much air in should it?

 

[boxer246]

Ok so I finally got the new loader valve installed yesterday. But, the loader will still not consistently lift or roll....it spits lots of air and foamy hyd oil through the breather depending on what position I manipulate the controls.....when I bounce up and down on the bucket it is like a pogo stick....obviously lots of air in the cylinders. I have not been able to run it through a complete cycle, it wont even do that. I would think by now with all the air that it has been spitting out the breather it would have worked out the air from the cylinders. Maybe it is sucking air in somewhere, I dunno. There is no hyd leaks on the suction side of the pump. The pump shaft seal is weeping oil, but I wouldn't think that would be letting that much air, if any, in the system. I'm at work today, but tomorrow I'll try it again and see if I can get it to completely cycle through a lift and roll and maybe that will work the air out.

Another thing I was thinking.....if the internal seals in the cylinders are bad, what symptoms would this show? None of the cylinders are leaking oil, so nothing obvious there.

I guess also I need to set up a pressure gauge like JJ said. I'll work on that if I cant get the thing to work.

 

[J_J]

If all vales are in neutral, is the air still coming out the breather.

If it is, then you have a suction leak. Try putting all around the suction pipe fittings and the pump itself .

When you try to lift the loader arms, hold the lever until the relief goes off on the end of extend and retract.

 

[boxer246]

Ah HA!!!!! Finally figured out the doggone thing!
Basically, I had the reservoir vent on the wrong side tower. So, the pump sucks fluid from the left side tower......but the right side tower is connected to the left by a 1/2" hose to crossfeed fluid, well, I had the breather on the right side tower, where the "out" hose from the loader valve dumps into. So there was not enough fluid in the left side tower to constantly feed the pump. The crossfeed wasn't fast enough because the fluid from the right side was basically just gravity crossfeeding into the left side tower. So, with no breather on the right tower, I think now the "out" side pushes fluid into that tower and it sort of pressure feeds the crossfeed tube, thereby supplying the left reservoir with a more consistent supply. SO the system is only vented on the left tower now.
Immediately when I had this idea, I switched them, and the loader worked perfect, instantly. Hopefully it stays that way.

However I do see one problem still.....the loader arms drift noticeably after shutting the tractor down. Now there doesn't seem to be any obvious fluid leaks, but does this mean the internal seals are bad on the cylinders, or is there something that needs adjusted on the valve? Or what?

Lastly, I did cheap out and bought the Walvoil valve that is pretty basic, no float or regen.....thats OK for what I need to do. But, I noticed the lift and curl functions do not work simultaneously.....is this just a function of this being a cheaper valve?

Thanks to everyone for their input.....now I have plenty of jobs for this little beast

 

[J_J]

With levers in neutral, the cyls should be locked.

If you raise the loader arms up and shut the engine off, if the lift arms drift down, it is a good bet that the cyl seals are leaking.