Front hydro pump to rear pto pump advise

Mjordan

Member

Equipment
Kubota L295
Sep 7, 2020
44
4
8
Indiana
Hello all. Searching some advice on hydraulic pumps. I have an L295 with a FEL that the hydraulics run off a pump mounted on the front of the crankshaft. It pulls the engine down tremendously, so I have to rev the tractor for it to operate. I am asking if I were to convert this to a pto pump what might I be looking for? I understand the rpms are less on the pto

looking for any advise or thoughts

thank you
 

torch

Well-known member

Equipment
B7100HSD, B2789, B2550, B4672, 48" cultivator, homemade FEL and Cab
Jun 10, 2016
2,621
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Muskoka, Ont.
I assume it bogs down even when running at high throttle settings? These engines are designed to make best power and torque up near full throttle. If it doesn't bog down at full throttle, then that's probably the way it was intended.

It will take the same amount of power from the engine to lift the bucket no matter how you drive the pump. Power = torque x speed. If your engine has lots of torque, you can generate the required power at lower speed than if the engine has less torque.

Since you can't change the engine's torque (well, not without adding a turbo or something), then you can reduce the speed at which you are lifting the load. Three ways to do that: gear down by using the PTO to drive the pump, replace the pump with a smaller one, or increase the diameter of the lift cylinders.

The first assumes the existing pump is not already geared down as much as the PTO by chain and sprockets between the crankshaft and the pump. If there are a chain and sprockets, that opens up a third possibility: changing the sprockets to provide a lower pump speed.

In all cases, you will have to run the engine at a high RPM to make the power. "So why bother, I'm already running it at high RPM because it is bogging down?" you might well ask. My response would be that it is easier on the engine to run it at a constant high rpm and demand within it's torque curve than it is to have the engine bog down because it doesn't have enough torque to meet the demand.
 

TheOldHokie

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Hello all. Searching some advice on hydraulic pumps. I have an L295 with a FEL that the hydraulics run off a pump mounted on the front of the crankshaft. It pulls the engine down tremendously, so I have to rev the tractor for it to operate. I am asking if I were to convert this to a pto pump what might I be looking for? I understand the rpms are less on the pto

looking for any advise or thoughts

thank you
How big is that front pump? Loaders don't require much in the way of flow and 10 GPM or less would be typical for a small loader. HP requirement for that is minimal. A crude rule of thumb is 1 HP for every 1 GPM of flow @ 1500 PSI. You have a 30HP diesel so unless you have a massive pump on there and tons in the bucket it should not be pulling the engine down.

My first suspicions would be a problem somewhere in the hydraulics or the loader mechanism. Or a very tired engine.

Dan
 
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BruceP

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G5200H
Aug 7, 2016
851
368
63
Richmond, Vermont, USA
My first suspicions would be a problem somewhere in the hydraulics or the loader mechanism. Or a very tired engine.
This is my thought as well. If the hydraulics were not 'bleeding off' unneeded pressure, the engine would unnecessarily work a LOT harder. (and could wear things out pretty fast)

Perhaps the OP could better explain under what conditions " ...pulls the engine down tremendously... ".

I would suggest IDENTIFYING and FIXING the problem rather than moving pump to the PTO. That sounds a bit like replacing your car 'cuz the tires are low on air.
 

rbargeron

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L5450, L48, L3250, L345 never enough attachments
Jul 6, 2015
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western ma
The front-mounted crank-driven pump was the "upgrade" option - over the standard internal pump for the hydraulics. It puts out more flow, but if yours is loading the engine it is likely plumbed wrong somewhere, forcing oil over a relief valve.

The FEL on that tractor ordinarily goes up and down effortlessly - can operate the pump with a cordless drill when its out of the coupling.
 
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Dave_eng

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M7040, Nuffield 465
Oct 6, 2012
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Williamstown Ontario Canada
Look for a label on the pump and post the info here.

Is there a model number on the loader?

What is the history of the tractor and this pump.

Most owners of older L's would want an engine driven pump.

Change any hoses lately? A hose in the wrong place on the loader valve can cause serious issues.

Has the loader valve been changed?

Something is wrong!

Dave
 
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TheOldHokie

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When the L295 was new the front-mounted crank-driven pump was the "upgrade" option - over the standard internal pump for the hydraulics. If yours is loading the engine it is likely plumbed wrong somewhere, forcing oil over a relief valve.

The FEL on that tractor goes up and down effortlessly - can operate the pump with a cordless drill when not in the coupling.
I am not familiar with that equipment but have put crankshaft driven front pumps on many tractors. I would think the plumbing on the L295 system should be GI proof. Usually just a standalone reservoir, pump, and vanilla open center DCV with pump and reservoir lines. Is the L295 more elaborate?

Dan
 

rbargeron

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I am not familiar with that equipment but have put crankshaft driven front pumps on many tractors. I would think the plumbing on the L295 system should be GI proof. Usually just a standalone reservoir, pump, and vanilla open center DCV with pump and reservoir lines. Is the L295 more elaborate?

Dan
Hi Dan - no- the front pump was part of an optional external tank-and-pump kit for the 1720 loader (fit l295, l305, l345, l355 models). Valve was usually a Cross BA. Nothing unusual.
 

Mjordan

Member

Equipment
Kubota L295
Sep 7, 2020
44
4
8
Indiana
Thank you all for your responses. I will see what pump I have and post. My engine is “tired” for sure, even when lifting with no load the tractor has to be atleast half throttle. More to come sirs. Happy 4th of July weekend!!!
 

BruceP

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Equipment
G5200H
Aug 7, 2016
851
368
63
Richmond, Vermont, USA
My engine is “tired” for sure, even when lifting with no load the tractor has to be atleast half throttle.
If you feel inclined, you can help isolate the problem by disconnecting one end of the hydraulic cylinder and recheck if the engine struggles to move it by itself. The engine should NEVER struggle to move the piston.

This would tell you if the issue is mechanical (joints of the loader) or within the hydraulic system.
 

torch

Well-known member

Equipment
B7100HSD, B2789, B2550, B4672, 48" cultivator, homemade FEL and Cab
Jun 10, 2016
2,621
871
113
Muskoka, Ont.
Do you have a heavy 3ph implement? Does the engine struggle to lift it? Since that is a completely separate hydraulic system it might confirm if the issue is the engine or the hydraulics.
 
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Mjordan

Member

Equipment
Kubota L295
Sep 7, 2020
44
4
8
Indiana
thank you all for the replies. I have been absent for quite some time and my apologies. I just posted a question on replacing my front axle seals and saw that i really did not make a full circle on this question. I am quite sorry. The engine does not "labor" at all with the 3 point system, nor does the power steering that I have running off of it. The loader is the only think that nearly kills the tractor unless atleast over 1/2 throttle. I will do more investigation on the pump and the hydraulics. I have only had this tractor for 3-4 years and have done alot of work to it to get it to this stage. More a hobby than anything. Thank you all.
 

Mjordan

Member

Equipment
Kubota L295
Sep 7, 2020
44
4
8
Indiana
If you feel inclined, you can help isolate the problem by disconnecting one end of the hydraulic cylinder and recheck if the engine struggles to move it by itself. The engine should NEVER struggle to move the piston.

This would tell you if the issue is mechanical (joints of the loader) or within the hydraulic system.
Hello Bruce, sorry it has been so long getting back. I did take off one of the cylinders and found that it does not change the problem. I did discover though that it only struggles to stay running when I am lowering the loacer and not raising. Hydraulics on the tilt bucket seem to work fine. So, the tractor seems to almost, and will, die if the rpm's are not 1/2 throttle when the loader is being let down.

Any suggestions? Thank you sir. Mark
 

Mjordan

Member

Equipment
Kubota L295
Sep 7, 2020
44
4
8
Indiana
Do you have a heavy 3ph implement? Does the engine struggle to lift it? Since that is a completely separate hydraulic system it might confirm if the issue is the engine or the hydraulics.
Yes sir, the 3 point attachments work fine. It is for sure the loader hydraulics. Thank you for replying
 

Dave_eng

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M7040, Nuffield 465
Oct 6, 2012
5,239
1,022
113
Williamstown Ontario Canada
Yes sir, the 3 point attachments work fine. It is for sure the loader hydraulics. Thank you for replying
Sounds like loader valve hoses in the wrong place.
How many lines connect to your loader valve? 6 or 7.
Is there a separate pump at the front of the engine for the loader?
Clean the loader valve body and look for letters in the casting beside each hose port.
Once you have these letters, try and make a sketch showing where each hose runs
Dave
 

Fedup

Active member
Apr 6, 2016
247
71
28
Winchester
Hello Bruce, sorry it has been so long getting back. I did take off one of the cylinders and found that it does not change the problem. I did discover though that it only struggles to stay running when I am lowering the loacer and not raising. Hydraulics on the tilt bucket seem to work fine. So, the tractor seems to almost, and will, die if the rpm's are not 1/2 throttle when the loader is being let down.

Any suggestions? Thank you sir. Mark
That certainly sounds more like a plumbing problem than a pump issue. I think you need to revisit that.
 

Mjordan

Member

Equipment
Kubota L295
Sep 7, 2020
44
4
8
Indiana
Sounds like loader valve hoses in the wrong place.
How many lines connect to your loader valve? 6 or 7.
Is there a separate pump at the front of the engine for the loader?
Clean the loader valve body and look for letters in the casting beside each hose port.
Once you have these letters, try and make a sketch showing where each hose runs
Dave
Thank you Dave. I will do that and get back to you with a sketch and pictures. I greatly thank you for your help sir
 

TheOldHokie

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L3901/LA525, B7200DT/B1630, G2160/RCK60, G2460/RCK60
Apr 6, 2021
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windyridgefarm.us
Thank you Dave. I will do that and get back to you with a sketch and pictures. I greatly thank you for your help sir
If I understand your situation corrwctly your loader has a crankshaft driven pump and is independent of the tractor hydraulics. Its a really simple system to trouble shoot.

Dan
 

Mjordan

Member

Equipment
Kubota L295
Sep 7, 2020
44
4
8
Indiana
Sounds like loader valve hoses in the wrong place.
How many lines connect to your loader valve? 6 or 7.
Is there a separate pump at the front of the engine for the loader?
Clean the loader valve body and look for letters in the casting beside each hose port.
Once you have these letters, try and make a sketch showing where each hose runs
Dave

Hello Dave, I have attached a sketch. It is pretty simple. I have also traced the hydraulic lines from the valves to the cylinders and all are going to the appropriate places on the cylinders. I am replacing the hydraulic pump on the front crankshaft as when I was removing it the housing cracked. I had to remove the loader to replace the fan belt, I am also going to paint it up while everything if off of it. Any suggestions are appreciated. The control valves do leak a bit, not much at all, on the lever that raises and lowers the loader. It seeps from the plunger that is connected to the lever and goes into the valve. Thank you again for your help sir. Mark
 

Attachments

Mjordan

Member

Equipment
Kubota L295
Sep 7, 2020
44
4
8
Indiana
Hello Dave, I have attached a sketch. It is pretty simple. I have also traced the hydraulic lines from the valves to the cylinders and all are going to the appropriate places on the cylinders. I am replacing the hydraulic pump on the front crankshaft as when I was removing it the housing cracked. I had to remove the loader to replace the fan belt, I am also going to paint it up while everything if off of it. Any suggestions are appreciated. The control valves do leak a bit, not much at all, on the lever that raises and lowers the loader. It seeps from the plunger that is connected to the lever and goes into the valve. Thank you again for your help sir. Mark
Sounds like loader valve hoses in the wrong place.
How many lines connect to your loader valve? 6 or 7.
Is there a separate pump at the front of the engine for the loader?
Clean the loader valve body and look for letters in the casting beside each hose port.
Once you have these letters, try and make a sketch showing where each hose runs
Dave

If anyone is looking for more information on the pump, the pump is an original gear pump that came with the loader. It is a Webster 077YC001701 LF. I am replacing it with a comparable pump as to save some dollars from the Webster.