3pt backhoe issues

Cmcinville · Mar 31, 2023

trying to convert a 3pt backhoe to a pto driven pump with tank. the pto pump has one small hydraulic style hose and one large 1.25" large slip on type hose. The backhoe VALVE has a hose that was hooked to the old tractor that is marked IN and another hose marked OUT. This is marked on the backhoe valve body. I have the IN hose (BACKHOE VALVE) running to the small hose on the pto pump. I have the OUT (BACKHOE VALVE) hose running to the small fitting in the 5 gal hydraulic tank. The large hose on the tank runs to the large hose on the pto pump 1.25" DIAMETER slip on type hose with regualer hose clamp. My issue is the backhoe unit started working just moved a little slow but would dig dirt. After a few minutes running the large 1.25" hose sucked in and collapsed. the backhoe still worked but moved much slower. So i redone this 1.25" hose with a hard pipe. After installing the hard pipe the backhoe moved for about half a minute and will do nothing now. is the pump bad? My main question is do i have the hoses run right.

BarnyardEngineering · Mar 31, 2023

If you didn't have the hoses run right it would not have worked at all. Pressure on the slip fit hose would have blown it out.

The suction hose collapsing indicates the pump is starving for oil. Do you have enough oil in the reservoir? Do you have the right kind of oil in the reservoir (i.e. not 85W-140 gear oil or road tar)?

What kind of pump is it? Was it new when you started? Where is the reservoir in relation to the pump (should be above for best results)?

Steve@Advance · Mar 31, 2023

What's inside the tank?

Sounds like a clogged suction strainer.

Jim.ME · Mar 31, 2023

To add to BarnyardEngineering's post. Is the suction hose wire reinforced (spiral wire in the hose to help prevent collapse) and rated for hydraulic oil service? 5 gallons may be too small a reservoir for the pump. Is the reservoir vented?

This post was edited by Jim.ME on 03/31/2023 at 07:13 am.

Cmcinville · Mar 31, 2023

Im not sure of the pump name it came off a wagner loader that worked. I am using regular hydraulic oil 46 i think. THE tank
is full 5 gallons. It does seem like its starving for fluid. i know the fluid seems to run out slow but, its think. I dont
mind buying a new pump instead of this old one but, would like to get it working right before, i spend money

Cmcinville · Mar 31, 2023

no strainer its a brand new tank and hoses

Cmcinville · Mar 31, 2023

The tank is brand new 5 gal. the filler cap looks to be vented. I do believe the problem may be its not getting enough fluid to the pump from the tank I guess i could try to put the rubber hose back on and see if it will move again.

Janicholson · Mar 31, 2023

I would take the cap off of the reservoir (maybe tie a rag over it to keep out dirt) then give it a try. If there is air in the system, it can compress and make suction if not vented. It needs to operate for an hour or so to assure no air is in it. A spring put in the rubber hose id probably better than a solid pipe unless there is some option for flexing that rigid pipe. it can fatigue. Jim

used red MN · Mar 31, 2023

Hello CM welcome to YT! My question is where is the
reservoir located in relation to the pump, so in simple
terms what is the level difference? It would be ideal if
you could post a couple pictures of the configuration.
Pictures post through the ..Choose files.. button just
below where it says ..Upload Photos/Videos.. down
lower in the ..New post and reply windows, see picture.
They cannot be pasted into the text area as a file.

Also when you say you have the return going into the 5
gal. tank with a ..small.. fitting tells us nothing. If you
know the National Pipe Thread ..NPT.. size tell us what
they are. I am attaching a pipe thread sizing chart. Did
you run the system before with hydraulic hoses
connected to your tractor remotes? Did is work fine
that way? Just making sure this is not the first time the
hoe has been operated in a while and some
accumulated debris is not being flushed out
contaminating the system and giving you problems.

NPT chart

Cmcinville · Mar 31, 2023

I plan on putting the rubber hose back on and maybe taken the filler cap off while running it. It does appear that the pump is not getting enough fluid to it. I do have the tank located about 2 feet above the pto pump. A spring may help with the hose collapsing I agree. I will try these things over the weekend. Thanks for advise

moresmoke · Mar 31, 2023

The hose collapsing means the pump is pulling vacuum on the suction side. Loosen the cap and try again.

Also keep in mind you want to have about 3 gallons of oil in your 5 gallon tank. Any cylinders that are retracted will add oil to the tank. You dont want it to run over.

caterpillar guy · Mar 31, 2023

A few things. I think your return hose to the pump from tank is to small, it needs a wire reinforced hose or other method than metal line. It will eventually crack break the metal line if it moves at all. Then what oil are you using in it. Heavy oil will not flow well and in cold weather will starve a pump. I would use some regular THF ( tractor hydraulic fluid). If there is a filter it might be restricting flow. Then I'm not sure you have enough reservoir for the pump, yes it is only pumping from one side to the other of the cylinders but cooling can become an issue with the low volume of oil. then level of reservoir in relation to pump might also starve pump. watch for any kinked lines as you operate the hoe those will do what you are saying also. We had an old Shawnee hoe decades ago we connected to the couplers on the tractor then just tied the lever. This was on an 830 Case worked fine like that.

MKinON · Mar 31, 2023

Is the tank vented to atmosphere. It needs to be.

sandcastle1 · Mar 31, 2023

5 gallons might not be enough, I presume you have down riggers to support the backhoe, now you start running the hoe and running out of oil could happen quickly.

Fritz Maurer · Mar 31, 2023

I would think a psi or two would be beneficial by
pushing the oil toward the pump.

showcrop · Apr 1, 2023

I used to have a PTO powered hoe. the tank was under 5 gal but the vent was a high volume affair, at least one inch with a high flow cap on it. I agree with the majority here that the vent is the problem, and of course it is easiest to check.

Fritz Maurer · Apr 1, 2023

After you changed to the steel suction line you dont
say whether the speed of the backhoe changed or
not. If the pump is matched to the loader -and- if the
cylinders on the loader are smaller than the ones on
the backhoe , your present speed is not going to
improve without a bigger pump. Working for 30
seconds and stopping does not sound like a supply
issue to me .... possible failed relief valve or you left
a rag in the pump when you built the pipe.

3pt backhoe issues

Cmcinville

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BarnyardEngineering

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Steve@Advance

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Jim.ME

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Cmcinville

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Cmcinville

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Cmcinville

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Janicholson

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used red MN

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Cmcinville

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moresmoke

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caterpillar guy

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MKinON

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sandcastle1

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Fritz Maurer

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showcrop

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Fritz Maurer

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