No PTO pump pressure

[CMR]

Where is the filter at? Between the tank and the TEE? Or between the TEE and the pump?

Between T and pump as I said before

 

[LD1]

If the filter is between the tee and the pump it's a suction filter and you are fine. This is the first time you have given an accurate enough description we know where it is. Fluid is only flowing one way across it. No problem.

No, it is not logical thinking to believe that the line between tee and pump is both suction and return.

Again, your lack of understanding the terminology, then not accepting the correct terms when told is adding to confusion.

The pipe or hose....from the tank all the way up to and including the tee is simply an extension of the tank.

You have two distinct likes, suction and return. They are not the same, never the same, and no part you your setup can be called both.

Using your logic....you could call the return line a pressure line. Since all of the fluid on that line was once in the pressure line. Hell you could call the pressure line a suction line by the same logic.

One your return hits the tee....return ENDS. From that point forward, no part of it is return

 

[LouNY]

A lot of Peeing in the coffee cups today.
The OP's system wasn't unusual 40 years ago.
Today it would not be made for a few reasons. The filter being located between the tee and pump is a suction filter.
Suction filters or screens are usually used in a good system a return line filter is also used. The suction screens or filters filter out the coarse
contaminates that will rapidly damage the pump and valve often being a 50 mesh screen or 50 or 25 micron filter. At the same
time the return line filter can be a 10 micron filter to catch the smaller particles and maintain a cleaner oil.
One issue commonly found with the single line tank setup is moisture contamination of the fluid as much of the fluid lies stagnate in the tank,
the other issue that is quite common when one of these older systems gets worked hard is the temperature rise of the pressurized fluid as it is not circulated through the reservoir which also acts as a heat sink to cool the oil over temperature conditions can occur.
Also the top of the reservoir should be vented other wise pressure and vacuum conditions will be created in the system,
this will cause either vacuum leaks into or pressure leaks out of the system or both.

 

[wdchyd]

FWIW, I have seen some old Gresen spin on filters that were actually 100 mesh screens internally when opened up. Maybe someone down the line mistakenly replaced one of these with a paper type normal everyday return line filter element.
That said I don’t like paper element filters used on the suction lines of any circuit, though it may work sometimes it usually ends up with bad mojo when it gets cold.

 

[CMR]

FWIW, I have seen some old Gresen spin on filters that were actually 100 mesh screens internally when opened up. Maybe someone down the line mistakenly replaced one of these with a paper type normal everyday return line filter element.
That said I don’t like paper element filters used on the suction lines of any circuit, though it may work sometimes it usually ends up with bad mojo when it gets cold.

Like I said before, I used a hydraulic filter, Napa 1551. I suspect it is up to the task

 

[CMR]

A lot of Peeing in the coffee cups today.
The OP's system wasn't unusual 40 years ago.
Today it would not be made for a few reasons. The filter being located between the tee and pump is a suction filter.
Suction filters or screens are usually used in a good system a return line filter is also used. The suction screens or filters filter out the coarse
contaminates that will rapidly damage the pump and valve often being a 50 mesh screen or 50 or 25 micron filter. At the same
time the return line filter can be a 10 micron filter to catch the smaller particles and maintain a cleaner oil.
One issue commonly found with the single line tank setup is moisture contamination of the fluid as much of the fluid lies stagnate in the tank,
the other issue that is quite common when one of these older systems gets worked hard is the temperature rise of the pressurized fluid as it is not circulated through the reservoir which also acts as a heat sink to cool the oil over temperature conditions can occur.
Also the top of the reservoir should be vented other wise pressure and vacuum conditions will be created in the system,
this will cause either vacuum leaks into or pressure leaks out of the system or both.

 

[CMR]

I’m looking for a vent with the 3/4 NPT I have, I think it will prevent condensation and evaporate water. I really haven’t had any leakage except from infrequent repairable seals. It only gets fluid by gravity, so there’s not much pressure inside that tank. Next to none. You haven’t said how an unventilated filler cap increases pressure

 

[CMR]

I’m looking for a vent with the 3/4 NPT I have, I think it will prevent condensation and evaporate water. I really haven’t had any leakage except from infrequent repairable seals. It only gets fluid by gravity, so there’s not much pressure inside that tank. Next to none. You haven’t said how an unventilated filler cap increases pressure

Oh ok you said pressure increases as the heat increases the volume of the fluid. That’s not much pressure. I appreciate the suggestion to get a line filter for the ten micron filter instead of the 50. I’ll look into that.

 

[CMR]

If the filter is between the tee and the pump it's a suction filter and you are fine. This is the first time you have given an accurate enough description we know where it is. Fluid is only flowing one way across it. No problem.

No, it is not logical thinking to believe that the line between tee and pump is both suction and return.

Again, your lack of understanding the terminology, then not accepting the correct terms when told is adding to confusion.

The pipe or hose....from the tank all the way up to and including the tee is simply an extension of the tank.

You have two distinct likes, suction and return. They are not the same, never the same, and no part you your setup can be called both.

Using your logic....you could call the return line a pressure line. Since all of the fluid on that line was once in the pressure line. Hell you could call the pressure line a suction line by the same logic.

One your return hits the tee....return ENDS. From that point forward, no part of it is return

I don’t see how I could attempt to claim a pressurized supply line could pass as a suction line, you’re really grasping at straws there aren’t you? Let’s just say the only return is from the valve to the T then, and anything with suction is just suction line. That’s fine. So the filter is on a suction line. But you have to agree that the fact remains that some of the fluid, probably 90% of it, is not going to the tank, and IS being suctioned through the filter, right?

 

[CMR]

I don’t see how I could attempt to claim a pressurized supply line could pass as a suction line, you’re really grasping at straws there aren’t you? Let’s just say the only return is from the valve to the T then, and anything with suction is just suction line. That’s fine. So the filter is on a suction line. But you have to agree that the fact remains that some of the fluid, probably 90% of it, is not going to the tank, and IS being suctioned through the filter, right?

I get the 90% estimate by virtue of the fact that the return from the valve is entering the T while the pump is sucking on the T, so why would return fluid instead go into the bottom of the tank. It’s primarily circulating in a pump to valve circuit. Which includes the

 

[CMR]

I get the 90% estimate by virtue of the fact that the return from the valve is entering the T while the pump is sucking on the T, so why would return fluid instead go into the bottom of the tank. It’s primarily circulating in a pump to valve circuit. Which includes the

Filter

 

[wdchyd]

51551 wix micron rating - Google Search

it’s a 10 micron filter element, that’s pretty fine when used for a suction filter anywhere. Older Gear pump equipment usually uses filter elements of 25 micron.

 

[CMR]

Thank you, I saw that too. Well I’ll just keep an eye on it and if it doesn’t flow fast enough I’ll lose power but the pump won’t go dry. I’ll worry about it then. . It’s an old pump and I’ve got two spares. But I doubt it’ll get damaged before it shuts the loader down. I’ll get a 25 micron next year.

I like the filter between the pump and both the tank and the valve, on the suction. The old tractors just had screens on the tanks, so a 25 will be fine.

 

[LD1]

I don’t see how I could attempt to claim a pressurized supply line could pass as a suction line, you’re really grasping at straws there aren’t you? Let’s just say the only return is from the valve to the T then, and anything with suction is just suction line. That’s fine. So the filter is on a suction line. But you have to agree that the fact remains that some of the fluid, probably 90% of it, is not going to the tank, and IS being suctioned through the filter, right?

I dont know why you are still wanting to argue about this.

Its very clear you have little to no understanding of hydraulics. Not trying to be mean or throw insults.....just being honest.

So why are you continuing to want to argue with me about trying to HELP you understand.....

By YOUR logic.....90% of the oil coming out of the return line is entering the suction line....therefore you call the suction line a return line.....

Well 100% of the oil coming out of the pressure line is going into the return line.....so by YOUR flawed logic....that would make the return line a pressure line.

You seem to think that one of those makes sense and the other does not. Well they BOTH dont make sense.

Quit visualizing the line from the tank to the tee and the tee as lines. View them as part of the TANK....and it should all make more sense.

I may be wrong.....because "tone of voice" isnt depicted in written word.....but I sense a little attitude. All we are trying to do is help. The constant "like I said before" comments, or claiming that I am grasping at straws like....gives me the impression that you know more about hydraulics than those you are seeking help from.

 

[oldnslo]

Thank you, I saw that too. Well I’ll just keep an eye on it and if it doesn’t flow fast enough I’ll lose power but the pump won’t go dry. I’ll worry about it then. . It’s an old pump and I’ve got two spares. But I doubt it’ll get damaged before it shuts the loader down. I’ll get a 25 micron next year.

I like the filter between the pump and both the tank and the valve, on the suction. The old tractors just had screens on the tanks, so a 25 will be fine.

CMR
Your thinking is a little flawed in that losing flow won’t damage the pump. A starving pump is cavitation which will destroy the pump. Having spares is nice but where is the debris created by cavitation going? Answer is into the rest of your system.

 

[CMR]

I dont know why you are still wanting to argue about this.

Its very clear you have little to no understanding of hydraulics. Not trying to be mean or throw insults.....just being honest.

So why are you continuing to want to argue with me about trying to HELP you understand.....

By YOUR logic.....90% of the oil coming out of the return line is entering the suction line....therefore you call the suction line a return line.....

Well 100% of the oil coming out of the pressure line is going into the return line.....so by YOUR flawed logic....that would make the return line a pressure line.

You seem to think that one of those makes sense and the other does not. Well they BOTH dont make sense.

Quit visualizing the line from the tank to the tee and the tee as lines. View them as part of the TANK....and it should all make more sense.

I repeat: I am not arguing the terminology. I’ll call those pipes whatever you want to call them. Im more interested in your initial assertion that the location of the filter was wrong. Now, we agree that 90% of the fluid coming down the return line goes to the filter then the pump. Which I say is a good setup. So tell me how it’s wrong, and what you think
As to your insult that I know nothing about hydraulics, I might not know as much as you, but who found the problem? Yours truly figured out it was an air lock problem. I cracked the output on the pump and got the air out. Now, let’s quit the personal attacks, nobody is perfect, and look at this objectively. I’m asking you what would you do to improve this setup. I’m not tapping into the tank for the return line. So I can put the filter between the valve and the T but I like filtering the tank outflow too so I don’t really see a perfect solution

 

[CMR]

CMR
Your thinking is a little flawed in that losing flow won’t damage the pump. A starving pump is cavitation which will destroy the pump. Having spares is nice but where is the debris created by cavitation going? Answer is into the rest of your system.

Yes into the rest of the system, IF it’s allowed to get that bad. So here’s my question to you. Let’s say you’re on the tractor loading manure or gravel. You’re busy with the controls. A hose bursts, you lose pressure, the controls no longer control anything, right? You’re out of commission. What do you do? Do you keep the engine and the OTO on? Hell no, you shut the thing off. Long before any damage occurs. Am I missing something? I can’t remember what started this conversation

 

[LouNY]

I think what he is trying to say and you are doing your best not to see;
is that restricted flow into the suction of a hydraulic pump will lead to cavitation in the pump from the low
pressure (actually a vacuum) at the inlet. This low pressure cavitation is more prone to occur with moisture
in a hydraulic system. You system will have moisture in it from the atmosphere even without a vented reservoir.
Which will also lead to a reduced suction pressure. That 15 micron filter on the suction if it does not have a
vacuum bypass will be extremely restrictive with cold oil. You are setting up a perfect situation for pump
suction cavitation which will erode minute pieces of steel or aluminum from your pump.

 

[CMR]

looks like I put my reply into the quote above, sorry about that. I’m still learning this forum stuff. My reply starts with “ I repeat, I’m not arguing the terminology.
Whatever you say the name of a line is that’s what it is. So where do you think I should put the filter? You said it belonged in the return line coming from the valve. If I do that it’s no longer filtering what little comes out of the reservoir. Not gonna tap the reservoir, the T stays. I appreciate your help. But don’t tell me I know next to nothing about hydraulics when it was me who found the problem. (Air lock)

 

[CMR]

I think what he is trying to say and you are doing your best not to see;
is that restricted flow into the suction of a hydraulic pump will lead to cavitation in the pump from the low
pressure (actually a vacuum) at the inlet. This low pressure cavitation is more prone to occur with moisture
in a hydraulic system. You system will have moisture in it from the atmosphere even without a vented reservoir.
Which will also lead to a reduced suction pressure. That 15 micron filter on the suction if it does not have a
vacuum bypass will be extremely restrictive with cold oil. You are setting up a perfect situation for pump
suction cavitation which will erode minute pieces of steel or aluminum from your pump.

I appreciate seeing that information, which is the first time I have seen it. You said “if it has vacuum bypsss”. If what has vacuum bypass? Not much moisture here in Montana, especially this year, but I’ve been running this loader 30 years now and it’s still hot the original pump. I only replaced the valve because the bucket tilt wasn’t holding down. And I think that was due to a stuck check valve but that’s just my guess. I figured some seal dried out somewhere from being in the sun 30 years. I’ve never heard of or seen cavitation before.