Loader refurbishing worse than when I starte

[GPintheMitten]

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.

OK, you're right Tom. Sorry.

 

[Coyote machine]

Something is clearly wrong, and until it is found you will continue to chase your tail, so let's see if we can stop that time wasting.
When you ran the tractor most recently and it boiled over, are we talking about the radiator boiled over and the tractor overheated? In what timeframe are we talking about that 'this' happened?

Here's what I might do. My thinking is to go down the line, one item at a time, starting with the most likely, and possibly easiest first, to see if change can be accomplished. We don't know what effect the 10 Micron filter is having on the circuit. To my knowledge 10 micron filters are fine for fluids like diesel or gas; not sure that hydraulic fluid can pass through fast enough to not cause problems like you have. Remove it and see what changes, if anything. Report result(s).
Is there anyway to determine where this pump is SUPPOSED to be mounted? Have you reached out to the Yanmar forum(s) guys to see if anyone has this pump on their tractor, and if it's mounted on front shaft or rear PTO? Is there a part # or anything at all to identify this pump?
Maybe a close inspection of the pump would show an arrow or some markings that indicate direction of intended flow.

I like the idea of using grease to find the suction (leak) point(s). And I really like the reversing of the fittings on the pump to hopefully get the flow of hydraulic fluid less restricted, and possibly solve the squealing, etc., BUT I wouldn't go to that effort until some of the other possibilities are explored.

If you don't have colored tape mark them with whatever you have and code them with magic markers or cable ties or similar.

Here's a link to a good explanation,IMHO, of what and where filters are to be mounted in a hydraulic system. Read through all the types and what it says about where they need to be mounted in relation to the tank and restrictive valves. (It's from the EU, but still applies to your situation).
Hydraulic Filters: Return Filter, Pressure Filter, Suction Filters, Parker Parfit Replacement Filters

 

[Djames55]

Looking at the above link this part...Return Line Filter... Link>Hydraulic Filters: Return Filter, Pressure Filter, Suction Filters, Parker Parfit Replacement Filters

It has a "NOTE: To prevent the hydraulic oil from foaming in the tank - in all operating conditions - the return flow must come from below the fluid level in the tank. As a general rule, the distance between the bottom of the tank and the end of the pipeline should be more than 2 to 3 times the pipe diameter." You have the filter returning at the top of the tank ABOVE the fluid... ? Could this be the air in the fluid and foaming problem? I don't know... I know nothing about Hydraulic... I'm reading and following this tread with interest, because I have this same valve I want to install on my tractor....

 

[skyhook]

I would now guess to say that the "front" pump is defective. Removing the "out" hose and putting it in a 5 gallon pail, then starting the tractor, you should see a steady stream of fluid, if it spits and sputters with air, you have found your problem. Just thinking out loud.

 

[woolyAcres]

When you ran the tractor most recently and it boiled over, are we talking about the radiator boiled over and the tractor overheated? In what timeframe are we talking about that 'this' happened?

I shouldn't have used the word 'boiled' (I went back and edited that post for clarity). Nothing is boiling. The hydraulic reservoir is bubbling over. It's not hot to the touch but there's so much air in it that it over-fills the tank.

Here's what I might do. My thinking is to go down the line, one item at a time, starting with the most likely, and possibly easiest first, to see if change can be accomplished. We don't know what effect the 10 Micron filter is having on the circuit. To my knowledge 10 micron filters are fine for fluids like diesel or gas; not sure that hydraulic fluid can pass through fast enough to not cause problems like you have. Remove it and see what changes, if anything. Report result(s).

If my attempts today to get the front fittings tightened up don't yield any results, I think I'll remove the filter to see what happens. This fluid is pretty thick and maybe it just can't get through there fast enough. The old system had something on it before returning to the tank, but I couldn't figure out what it was. Here's a photo taken right after I bought it. Here's a photo highlighting the mystery item. It's a disc shaped item, looks like a filter of some type but I couldn't figure out how to clean it and figure replacing would be better.

Is there anyway to determine where this pump is SUPPOSED to be mounted? Have you reached out to the Yanmar forum(s) guys to see if anyone has this pump on their tractor, and if it's mounted on front shaft or rear PTO? Is there a part # or anything at all to identify this pump?
Maybe a close inspection of the pump would show an arrow or some markings that indicate direction of intended flow.

Not sure what to make of this. I brought this up in the Yanmar forum back in the summer. This model does support a front PTO but that's not what I've got. There's no clutch or anything just a shaft sticking forward from the engine that can be coupled to the pump. I kinda doubt there's another one in the world setup like this. It looks like a custom job to me. I didn't move the pump so I think it's installed right where it's supposed to be. :thumbsup:

I'll have to be more willing to contort myself and lay in a puddle of fluid to see if there are any markings on the underside of the pump. Knowing the brand/model of the pump would be extremely helpful.

I like the idea of using grease to find the suction (leak) point(s). And I really like the reversing of the fittings on the pump to hopefully get the flow of hydraulic fluid less restricted, and possibly solve the squealing, etc., BUT I wouldn't go to that effort until some of the other possibilities are explored.

If you don't have colored tape mark them with whatever you have and code them with magic markers or cable ties or similar.

Here's a link to a good explanation,IMHO, of what and where filters are to be mounted in a hydraulic system. Read through all the types and what it says about where they need to be mounted in relation to the tank and restrictive valves. (It's from the EU, but still applies to your situation).
Hydraulic Filters: Return Filter, Pressure Filter, Suction Filters, Parker Parfit Replacement Filters

I can turn the pump shaft by hand in either direction so I don't think anything is bound up. Thanks for the link to the filter discussion. I don't see anything in there that suggest the filter I have is wrong or in the incorrect place.

 

[LD1]

If you have the valve plumbed according to the pic linked, it is correct. Regen is on the first spool only, and effects only the curl. And very unlikely that regen is causing you any kind of air issues.

The two posts above have great points.

INSIDE the tank, how is the return line? You want to return fluid near the bottom of the tank. There is usually a pipe inside the tank directing the return flow toward the bottom.

And I like the idea of unhooking the valve from the circuit and seeing just what the flow is like coming directly out of the pump.

 

[woolyAcres]

Looking at the above link this part...Return Line Filter... Link>Hydraulic Filters: Return Filter, Pressure Filter, Suction Filters, Parker Parfit Replacement Filters

It has a "NOTE: To prevent the hydraulic oil from foaming in the tank - in all operating conditions - the return flow must come from below the fluid level in the tank. As a general rule, the distance between the bottom of the tank and the end of the pipeline should be more than 2 to 3 times the pipe diameter." You have the filter returning at the top of the tank ABOVE the fluid... ? Could this be the air in the fluid and foaming problem? I don't know... I know nothing about Hydraulic... I'm reading and following this tread with interest, because I have this same valve I want to install on my tractor....

This is a good point. When I was cleaning the tank out from all the old fluid I found a piece of 3/4" pipe laying on the bottom of the tank. When the return line enters the tank it makes a 90* bend and points straight down. I believe the 6" piece of pipe I found on the floor of the tank was meant to screw into this elbow. I put it back in there and tightened it down. The return fluid exits this pipe about 4" below the level of the fluid. This is still about 8-10" above the floor of the tank. So although this problem fits my situation, I think I've already addressed this particular cause.

 

[LD1]

This is a good point. When I was cleaning the tank out from all the old fluid I found a piece of 3/4" pipe laying on the bottom of the tank. When the return line enters the tank it makes a 90* bend and points straight down. I believe the 6" piece of pipe I found on the floor of the tank was meant to screw into this elbow. I put it back in there and tightened it down. The return fluid exits this pipe about 4" below the level of the fluid. This is still about 8-10" above the floor of the tank. So although this problem fits my situation, I think I've already addressed this particular cause.

4" below fluid level may still be a concern.

We dont know the GPM of the pump or the size of the pipe. It all comes down to flow velocity as to weather 4" under is acceptable.

If it were mine, I'd add more pipe and get down to ~3" off the floor

 

[woolyAcres]

4" below fluid level may still be a concern.

We dont know the GPM of the pump or the size of the pipe. It all comes down to flow velocity as to weather 4" under is acceptable.

If it were mine, I'd add more pipe and get down to ~3" off the floor

GPM of the pump is still unknown. The lines running to and from the pump are 3/4". However, the ports on the valve are SAE #8- so quite a bit smaller. I've probably got some other lengths of pipe around so I could extend this return further down into the tank.

 

[TomSeller]

If my attempts today to get the front fittings tightened up don't yield any results, I think I'll remove the filter to see what happens. This fluid is pretty thick and maybe it just can't get through there fast enough. The old system had something on it before returning to the tank, but I couldn't figure out what it was. Here's a photo taken right after I bought it. Here's a photo highlighting the mystery item. It's a disc shaped item, looks like a filter of some type but I couldn't figure out how to clean it and figure replacing would be better.
.

My guess it was some sort of screen, but it is hard to tell from that picture. You say the fluid is thick? Like gear oil? It should be fairly thin, like a very light motor oil.