Tank return hose diameter?

Cobra 7

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L2350DT
Oct 30, 2025
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96 Kubota L2350DT w/ loader

I added rear remotes to my tractor and was contemplating using 1/4 vs 3/8 for the tank return line. The tank return from loader is 3/8 and runs to the rear fill plug behind the seat. I was thinking of breaking that line and installing a tee for the rear controls tank return line. 1/4 line would give me more flexibility in such a cramped area.

I know I'm only about 4gpm flow, just wandering if coming from 3/8 supply to rear to a 1/4 discharge will create undesirable back pressure?
 

PoTreeBoy

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96 Kubota L2350DT w/ loader

I added rear remotes to my tractor and was contemplating using 1/4 vs 3/8 for the tank return line. The tank return from loader is 3/8 and runs to the rear fill plug behind the seat. I was thinking of breaking that line and installing a tee for the rear controls tank return line. 1/4 line would give me more flexibility in such a cramped area.

I know I'm only about 4gpm flow, just wandering if coming from 3/8 supply to rear to a 1/4 discharge will create undesirable back pressure?
I don't know how you're plumbing it but 1/4" hose is sufficient for 4.4 gpm.
 

85Hokie

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the 3/8 line has slightly twice the cross section area of the 1/4 diameter hose. .11 vs .049

This will increase pressure through the hose.

However 1/4 will handle that flow rate as PTB said.
 

Cobra 7

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L2350DT
Oct 30, 2025
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Alabama
I don't know how you're plumbing it but 1/4" hose is sufficient for 4.4 gpm.
Rear remotes are supplied by FEL power beyond. All 3/8 lines for supply from tractor to FEL and FEL to rear remotes. Tank return from FEL is 3/8 (which is where I would TEE into for rear control tank return). All lines to working cylinders (top link, side link) are 1/4.
 

PoTreeBoy

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Rear remotes are supplied by FEL power beyond. All 3/8 lines for supply from tractor to FEL and FEL to rear remotes. Tank return from FEL is 3/8 (which is where I would TEE into for rear control tank return). All lines to working cylinders (top link, side link) are 1/4.
Does your rear remote valve have tank and power beyond? Manual or solenoid? Just curious.
 

TheOldHokie

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96 Kubota L2350DT w/ loader

I added rear remotes to my tractor and was contemplating using 1/4 vs 3/8 for the tank return line. The tank return from loader is 3/8 and runs to the rear fill plug behind the seat. I was thinking of breaking that line and installing a tee for the rear controls tank return line. 1/4 line would give me more flexibility in such a cramped area.

I know I'm only about 4gpm flow, just wandering if coming from 3/8 supply to rear to a 1/4 discharge will create undesirable back pressure?
That will be fine but lets be clear about the line in question.

The tank line is ONLY used when the aux valve is shifted and a cylinder is retracting or extending. When the valve is in neutral all flow us going out power beyond.

Dan
 
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Cobra 7

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L2350DT
Oct 30, 2025
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Alabama
Does your rear remote valve have tank and power beyond? Manual or solenoid? Just curious.
[/QUOTE
It is a Summit P40 2 spool with Tank and PB out (which I plumbed back to where the Loader PB (power beyond) went back to the tractor.
 
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Cobra 7

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Equipment
L2350DT
Oct 30, 2025
6
1
3
Alabama
That will be fine but lets be clear about the line in question.

The tank line is ONLY used when the aux valve is shifted and a cylinder is retracting or extending. When the valve is in neutral all flow us going out power beyond.

Dan
That clears up a lot with me, I had assumed that tank was continuous flow as the fluid had to go somewhere on open system. So the tank return from AUX would not have to fight the tank return from FEL.

Thanks
 

TheOldHokie

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That clears up a lot with me, I had assumed that tank was continuous flow as the fluid had to go somewhere on open system. So the tank return from AUX would not have to fight the tank return from FEL.

Thanks
You are still a little confused.

When both valves are in neutral ALL flow is going through fhe power beyond circuit and nothing is goung out either tank port. That is the continuous flow (neutral) circuit.

When the AUX valve is operated the PB flow stops, the incoming oil is sent to the cylinders, and return flow from the cylinders is sent out tank.

Dan
 

Cobra 7

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L2350DT
Oct 30, 2025
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Alabama
You are still a little confused.

When both valves are in neutral ALL flow is going through fhe power beyond circuit and nothing is goung out either tank port. That is the continuous flow (neutral) circuit.

When the AUX valve is operated the PB flow stops, the incoming oil is sent to the cylinders, and return flow from the cylinders is sent out tank.

Dan
Thanks for the clarification.
 
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Cobra 7

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Equipment
L2350DT
Oct 30, 2025
6
1
3
Alabama
Did you get and install a PB adapter/plug in the valve?
Yes
My tractor was set up for PB for a backhoe (unfortunately for me the previous owner sold the backhoe) from the FEL. All I had to do was run the FEL PB to my P40 valve then out the P40 PB to back where my original PB hooked into the tractor.