Loader refurbishing worse than when I starte

[Coyote machine]

Is the pump not marked? In should say in for your suction and out for your pressure. There are quite a few fittings in that suction line from looking just at the pump end. What fluid did you use? Do your supply or tank hydraulic lines get very warm?

Soap on a suction line is not good if there is a leak, you would only do that on a pressurized line.

What would be a better indicator of a suction side leak, if not using soapy solution?

 

[TomSeller]

What would be a better indicator of a suction side leak, if not using soapy solution?

Maybe I am not clear on when the soapy water would be used. Since the tank is vented, I am under the impression his suction line has negative pressure and soap would be drawn in. Now if we are talking about disconnecting and pressurizing the line, yes, soapy water is perfect.

 

[ch1ch2]

It would not hurt to run the relief all the way to the lowest pressure as suggested above until you figure this out. A sketch of how you piped it would help in addition to the pictures.

A1 and B1 go to the same cylinder (Curl). A2 and B2 go to the same cylinder (Boom). Wouldn't hurt to check that. 1s go together and 2s go together. Not As and Bs. Diagram is in the PDF showing which port gets the rod end of the cylinders

http://www.brand-hyd.com/lv/catalog.pdf

I posted earlier about the regen.
I still believe that might be your problem.
The schematic says to hook up the boom to A+B 1 and the curl to A+B2
That is not how you have posted that you have it hooked up.

 

[GPintheMitten]

I just completed an overhaul of my tractor's (Yanmar YM240D) loader hydraulics. Now that everything is re-assembled I get a shuddering and screetching when I operate it and all 4 functions aren't working correctly. Could this just be air in the lines that hasn't been purged yet?

This overhaul included installing a new Brand Hydraulic joystick loader valve (replacing an older 2-lever arrangement) as well as moving the supply for this system from the tractor's main hydraulic pump to one that is mounted at the front and runs off a shaft sticking forward from the engine. The pump is working because I can see fluid returning to the tank. Raising the boom works okay but there is some shuddering and noise when doing so. Lowering works as well but there's shudder and screeching there. Curl and dump don't function as well, but during the overhaul, because the cylinders were vertical, with no hoses attached at one point, more fluid leaked out of them.

Additionally, the pressure relief valve (which should be set to 2000psi for this new valve) doesn't seem to be relieving pressure. I have a pressure gauge T'd into the system and it can/does spike at over 4000psi, nearly stalling the tractor.

Could this all be caused by air in the system that can/should bleed as I work through all the functions? Or should I be looking for other issues/solutions?

The noise and shuddering made me nervous enough to stop and think (and ask) about what's going on here. I don't want to damage the tractor, new loader valve, or anything else.

Thanks,

Regarding the possibility that the hoses are reversed on the pump ... I don't think so because there is some functioning of the lift arms.

The pegging of the guage over 4000 is a big clue and a big concern. I wonder if you have hoses from the loader plumbed incorrectly. A circuit is made up of an A1 and B1, and the other is A2 and B2. If you plumbed A1 and A2 to a cylinder and B1 and B2 to a cylinder it would be incorrect, but I don't know how it would behave.

I think you need to double check how you plumbed it from the loader control valve. This can be confusing, so look carefully. From the pictures, we can not trace where to lines go on the cylinders.

Also, double check the return to tank line is plumbed to the correct port on the valve.

 

[TomSeller]

I posted earlier about the regen.
I still believe that might be your problem.
The schematic says to hook up the boom to A+B 1 and the curl to A+B2
That is not how you have posted that you have it hooked up.

The diagram in the link on Page D21 says curl A1/B1 and Boom A2/B2. He has verified the connections and seems to have mostly just the frothing problem left.
http://www.brand-hyd.com/lv/catalog.pdf

 

[GPintheMitten]

Also, do you have any quick disconnects in the loader circuit? They could fail and prevent oil from circulating correctly. I had some loader curl function not working correctly. I tested and debugged a number of ways and thought that I had proven that they worked but in fact my methods were not complete. There was in fact a quick disconnect that had been damaged and needed to be replaced.

 

[GPintheMitten]

The diagram in the link on Page D21 says curl A1/B1 and Boom A2/B2. He has verified the connections and seems to have mostly just the frothing problem left.
http://www.brand-hyd.com/lv/catalog.pdf

I know what the diagram says. But an author can proofread his own words many times and still fail to find a mistake. I think another close and careful verification would be prudent. Besides, where did the 4000 come from? It could come from a block in the system. I don't know if plumbing it incorrectly would cause that or not. But I wouldn't expect air in the system would cause such a high pressure reading.

Also, he has more than frothing problem. He says it is shuddering and screaming.

 

[Coyote machine]

Maybe I am not clear on when the soapy water would be used. Since the tank is vented, I am under the impression his suction line has negative pressure and soap would be drawn in. Now if we are talking about disconnecting and pressurizing the line, yes, soapy water is perfect.

My idea is to use the soapy solution to be drawn into whatever fitting is sucking air into the system. We're not talking about a lot of liquid, just enough to pinpoint the leak. It's a vacuum condition, instead of a pressure one. Either way, I believe it could be used to find the site of any leakage of air into the suction side lines. I could be wrong, it happened once, I was told.

 

[wdchyd]

My idea is to use the soapy solution to be drawn into whatever fitting is sucking air into the system. We're not talking about a lot of liquid, just enough to pinpoint the leak. It's a vacuum condition, instead of a pressure one. Either way, I believe it could be used to find the site of any leakage of air into the suction side lines. I could be wrong, it happened once, I was told.

Are you getting air PRESSURE leaks mixed up with SUCTION leaks??

I use grease for suction leak detection but soapy water for pressure (air/gas ect).......it may work but, don't know if I want soapy water ending up in my hyd oil:2cents:

 

[TomSeller]

I know what the diagram says. But an author can proofread his own words many times and still fail to find a mistake. I think another close and careful verification would be prudent. Besides, where did the 4000 come from? It could come from a block in the system. I don't know if plumbing it incorrectly would cause that or not. But I wouldn't expect air in the system would cause such a high pressure reading.

Also, he has more than frothing problem. He says it is shuddering and screaming.

Here is the OP's report on the pressure from his earlier post:

"I confirmed the lines are connected correctly and in fact, after adjusting the pressure relief valve (down to 1000psi) things seem to be going better. I think maybe the relief valve was stuck. I plan to adjust it back upward to 2000psi but I've still got a problem to solve. It seems the system is really sucking air from somewhere. After running for about 3 minutes the tank overflowed because of all the air it had drawn in."

I am not sure but I think the shuddering and screaming may be resolved.