Loader refurbishing worse than when I starte

[woolyAcres]

The strainer is more difficult in that you have to drain the fluid.

This isn't plumbed into the normal 3Pt yanmar setup. Hopefully the images I uploaded will be more accessible and give a good idea of what I'm working with.

I drained and cleaned the tank before refilling. The cylinders had clean fluid in them (rebuilt them about 3 months ago). The only place there could have been junk, is in the suction line since I never removed it. The high-pressure line is brand new. When the fluid in the tank has been sitting I can look to see if there's anything in it. It should be pretty clean but it's worth checking.

How can I tell if my filter is letting air into the system?

 

[TomSeller]

I think the previous owner ignored this pump so it could easily be several years. When I got the machine, this 'loop' was still filled with very milky fluid.

When you say "loop" do mean the hoses at the pump/valve? If that is milky your tank likely would be as well. The white coloring is coming from water emulsified into the oil. Check the tank and if it is milky you definatley need to change the fluid and clean that strainer. Change the filter too if it has one.

 

[woolyAcres]

When you say "loop" do menthe hoses at the pump/valve? If that is milky your tank likely would be as well. The white coloring is coming from water emulsified into the oil. Check the tank and if it is milky you definatley need to change the fluid and clean that strainer. Change the filter too if it has one.

Hi Tom-

Thanks for your comments. By 'loop' I mean this particular hydraulic system. This tractor now has 2. The original one that runs the 3PT and this 'new' one that I'm dedicating to the loader. I put new in quotation marks because the tank, pump, and hoses were on the tractor when I bought it (used) but the pump wasn't connected to the engine and therefore didn't turn and the system was simply plumbed in a circle with no valve. Clearly someone moth-balled it. Prior to my conversion/re-furbishing, my FEL ran off the same system as the 3PT. I'm trying to get better performance by moving the loader to it's own system.

I'm using the original tank, pump, and suction hose. I drained all the fluid, replaced the valve, filter, pressure line from pump, and all the soft hoses on the FEL. Now when I engage the pump it makes the tank frothy. If I let that sit, the air settles out and I'm back to the clean, new fluid I put into it on Saturday. I got as much of the old milky fluid out as possible. I even primed the pump my turning it by hand to push new fluid through the system and expel the old stuff. I'm pretty comfortable that the fluid is good.

It's with this setup that I get some noise in the system and lots of air in the tank.

PDF 8 above shows the system and PDF 6 shows the pump.

 

[GPintheMitten]

I'm no expert but I would expect some air in the lines to start with but would also expect that to be burped through with a few cycles of the valves.

It sounds like you have much more air than that. Seems like air is getting reintroduced.

Is the tank full enough and large enough to fill the hoses and cylinders and still have enough in the tank? Can you observe the tank level when running?

If it is not the tank size or level then either the suction hose, filter or pump itself. Can you temporarily take the filter out of the loop just to make sure?

Replace the suction line would not be extremely costly.

By checking the above components, you should be able to determine if it is the pump.

Are you sure you have cycled it enough to purge air from the pressure side?

 

[LD1]

This might make a mess, because I dont know where on the tank the suction line is, but......

Unhook the suction line from the tank and adapt to an air fitting. Take the pressure line off the pump and put a plug in it there.

Would be nice to be able to keep the pump and suction hose full of oil if possible and not leak a ton of fluid on the bump or suction hose.

Now give it the air. If the suction hose is leaking, or pump seal leaking, the air pressure should force oil out and you will see the leak in the form of it getting wet with hydraulic fluid.

The issue has to be in the pump, suction hose, or level in the tank. Filter is in the return circuit and highly unlikely to be sucking in air, as the return is under slight pressure.

 

[GPintheMitten]

My mistake talking about the filter. I was thinking of it being on the suction line, not return to tank line.

 

[oldnslo]

This might make a mess, because I dont know where on the tank the suction line is, but......

Unhook the suction line from the tank and adapt to an air fitting. Take the pressure line off the pump and put a plug in it there.

Would be nice to be able to keep the pump and suction hose full of oil if possible and not leak a ton of fluid on the bump or suction hose.

Now give it the air. If the suction hose is leaking, or pump seal leaking, the air pressure should force oil out and you will see the leak in the form of it getting wet with hydraulic fluid.

The issue has to be in the pump, suction hose, or level in the tank. Filter is in the return circuit and highly unlikely to be sucking in air, as the return is under slight pressure.

Be very, very, very careful in pressurizing the pump inlet and or the reservoir. The shaft seal may only be good for around 10 PSI before it fails and the reservoir even less. Another possible problem with pressurizing suction lines is that pressure can seal a vacuum leak.

Yes on most pumps the shaft seals can be replace. May not even require dimantling the pump to replace them either.

 

[woolyAcres]

I'm no expert but I would expect some air in the lines to start with but would also expect that to be burped through with a few cycles of the valves.

It sounds like you have much more air than that. Seems like air is getting reintroduced.

I agree. The air in the cylinders returns to the tank in big bubbles/burps. What I'm getting is like a frothing wand on an espresso machine.

Is the tank full enough and large enough to fill the hoses and cylinders and still have enough in the tank? Can you observe the tank level when running?

That's a good question. I've got maybe 4' of 3/8" hose, the four cylinders, probably 20' of hard lines at 1/4", about 16' of flex 1/4", and about 12' of 3/4", plus the pump, and filter. My tank is probably about 4 gallons. I've got at least 4 gals in the system now with enough room to probably add one more gal to the tank before she'd over flow even without the froth.

Replace the suction line would not be extremely costly.

Not compared to what I've already spent on this... :shhh:

Are you sure you have cycled it enough to purge air from the pressure side?

I think there's still a little bit of air in the cylinders. But that shouldn't come out until I manipulate the joystick, right? Problem is, the pump runs anytime the engine is running. In the amount of time it takes to get the tractor started and warmed up so I can move it outside where I have enough height to run the bucket all the way up, the tank will overflow with froth...

 

[woolyAcres]

This might make a mess, because I dont know where on the tank the suction line is, but......

Suction leaves the tank about 1/2" above the bottom of the tank.

Unhook the suction line from the tank and adapt to an air fitting. Take the pressure line off the pump and put a plug in it there.

Would be nice to be able to keep the pump and suction hose full of oil if possible and not leak a ton of fluid on the bump or suction hose.

Now give it the air. If the suction hose is leaking, or pump seal leaking, the air pressure should force oil out and you will see the leak in the form of it getting wet with hydraulic fluid.

The issue has to be in the pump, suction hose, or level in the tank. Filter is in the return circuit and highly unlikely to be sucking in air, as the return is under slight pressure.

Try to push air in beginning where the suction line leaves the tank? How much pressure are we talking?

 

[woolyAcres]

Be very, very, very careful in pressurizing the pump inlet and or the reservoir. The shaft seal may only be good for around 10 PSI before it fails and the reservoir even less. Another possible problem with pressurizing suction lines is that pressure can seal a vacuum leak.

Yes on most pumps the shaft seals can be replace. May not even require dimantling the pump to replace them either.

Sounds like I need to figure out what pump I really have. If I was able to remove the pump from the tractor what's the best I could hope to learn?