Help ordering hydraulic fittings (for rear remote)

[rswyan]

A PB port must be a check valve. Is this correct?

No ... J J described what the power beyond function does above:

If you don't know, the PB adapter separates the flow from the expended cyl fluid and the relief flow, and allows the pump flow to continue downstream..

On the valve I used for the log lift on my splitter - and the valve for the rear remotes as well - I had to remove a (closed) plug in the valve body and install the optional power beyond fitting (which then provided an additional outlet) in order to have access to the power beyond feature.

IOW: the valve itself was power beyond capable ... but with out the optional fitting the capability isn't actually available.

Otherwise the FEL would drop.

I believe the individual sections or spools (piston) in the valve form the seal - these may contain internal check valves or "load checks" ...

 

[Sodo]

I believe the individual sections or spools (piston) in the valve form the seal - these may contain internal check valves or "load checks" ...

Spools would direct the flow to the chosen ports, and seal one circuit from the other, but if the flow can't go backwards thru the port there has to be a check valve.

 

[J_J]

No check except for the load check, and that prevents the load from dropping when you shift the spool, and also keeps the cyl flow from the input to the valve.

The pump is providing flow all valves i an open center hyd system, and the valve spools redirects the flow to where it is needed.

When you release the lever, the cyl is locked and the pump flow keeps flowing downstream.

Any spool can use the flow as long as the valve upstream does not use all the pump flow.

As a matter of fact, if a valve downstream tries to use the flow, it can cause back flow and work against the pump flow and cause problems.

You can also use two spools at the same time on some valves, but the speed of operation decreases, because you are splitting the flow.

 

[Sodo]

Good. The one port (that is unlabeled ?) should be the power-beyond outlet. It could be labeled "BY" or "PBY" I think.

OK it's labeled "PB" you can see it in the pic.

That is what I suspected ...

That may be a problem ... because it doesn't appear to have a power-beyond outlet ... and yet it is being used (via it's return) to provide power-beyond capability to another valve downstream of it (the internal valve inside the tractor that raises and lowers the 3PH) ... via the hose (labeled "supply" in your photo) that connects the rear valve to the mid hydraulic block.

This could be the case. What problem does this cause?

 

[J_J]

I explained all that in post #28.

Whoever did the remote installation, did not understand PB.

You should have the PB adapter in the remote valve PB port and feeding the rear hyd block, with tank line gong to tank.

Input for the rear hyd block is coming from the mid hyd block.

FEL PB should be feeding the mid hyd block IN port. Tank line to tank.

 

[Sodo]

Thanks very much for your help J-J. Truth be told I need someone who "almost understands" Hydraulics to translate your answer to a "regular guy".

When the valve that uses the tank port for supply is in a series flow path, any valve downstream can operate and cause back pressure and perhaps damage the valve seals or crack the casing, and cause problems with valves upstream.

Is there an undesirable system behavior that this causes? What problem might I notice during operation? Or is it a detriment to upstream components?

I can imagine a situation where a slug of fluid gets trapped between two valves, and then when a hose is bent the pressure can spike up, putting excessive pressure on the valves at each end. Considering my last component after the "missing" PB adapter" is a 3-pt hitch (not power-down) is it necessary to be remedy this? If I understand the problem, there can be no "excess pressure" because the hitch would just raise a millimeter (not a real problem). Is this correct here?

You should have the PB adapter in the remote valve PB port and feeding the rear hyd block, with tank line gong to tank.

To you think my Dinoil valve has a PB port, and can I add a PB adapter to it?

Input for the rear hyd block is coming from the mid hyd block.

I think I have this. Not clear if you are confirming this or recommending to remedy it?

FEL PB should be feeding the mid hyd block IN port. Tank line to tank.

I think I have this. Confirming or recommending remedy?

Pretty difficult to follow (for me) with no schematic. My thick skull needs either a schematic, or someone showing it to me on the tractor, and without that there's too many details to follow. I hope you don't mind if another member tries to help me understand your guidance. I really appreciate your attention J_J.

 

[J_J]

In post #34, you stated that you had a PB port.

If you have the PB adapter, install it and run the PB hose to the input to the rear hyd block and run the tank line to tank.

If you keep the tank port as is, you have the potential of damaging your valve.

If you look at the parts for your tractor, you can see the mid hyd block, and also see the optional hyd blk for the rear for a remote valve.

Any valve downstream can cause back pressure and affect any valve upstream.

When you do that, you can show relief pressure upstream and cause irregular functions of valve spools.

It is advisable not to operate two valves at the same time.

You can operate two spools in the same valve together, although at reduced speed.

I surely did think my answers were clear and concise for anyone to follow.

 

[Sodo]

Hi J_J, I've linked all the pics in one post.

My FEL valve has a port labeled PB, and it goes to the yellow-banded line on the small block at mid-tractor. What I've (incorrectly) labeled supply and rtn are the (only) two hoses that go to my rear hydr valve (a 3-spool Dinoil).

At this point I'm not clear if a hose going to the tractor case operates the 3-pt cylinder <---> or is just the return to tank. And what's on the other side of the mid-block? The pump? Check valves? Need a schematic, or someone holding my hand and following hoses on the tractor.

I surely did think my answers were clear and concise for anyone to follow.

I'm sure they are, but I don't even have a schematic to see what's connected to what, don't know the names of the components, and my tractor is 100 miles away. If I can't find a representative schematic I will (try to) make my own schematic (in a few days) when I get near my tractor.

I really appreciate your time and attention, and always like to understand the problem. And more importantly, if I ought to remedy this one, (and how to do it).

 

[J_J]

Do you have the rear hyd block?

A hard line from the mid hyd block carries the flow to the side of the rear 3pt assembly using a banjo fitting.

If the remote valve was installed using the rear hyd block, then the rear hyd block is supplying the remote valve using one port and the other port is supply hose going to the 3pt input, and tank line going to tank.

Pictures would help.

To fix things, every valve should have and Input and a PB supply line and of course a tank hose.

The last valve, the 3pt valve dumps into tank.

 

[Sodo]

Do you have the rear hyd block?

I don't know. Only recall one in the middle of the tractor but I will look again. Is a "block" just a simple "connection block"? Does it have other functions inside (check valves etc)?