Additional hydraulic pump.

[Mundy]

I have been wanting to add a seperate pump to power my FEL. The 4 GPM that my tractors pump puts out at 2700rpm is a little slow and I don't like to rev the tractor that much just to move the FEL faster.

I have worked out that I have room to add a pump to the front of the tractor between the bumper rails. There is already a pre formed hole in the radiator suport for a shaft.

Now for my question:
I would like to share the Hydraulic fluid that the tractor already uses for its own system with this additional pump.

I am thinking about tapping into the supply line already running to the tractors pump to also supply the new pump.
What problems do you guys see with this?

1) The tractors pump will only be powering the 3pt after the new pump is installed.
2) This current pump supply line is approx 7/8" and the presure line leaving the tractors pump is less than 1/2".
3) The return from the new pump would be tapped into the tank at its own location.
4) The new pump will be no more than 10 GPM.

What size line is common to supply a 10GPM pump?

Would too small of a supply just starve the pumps a little and reduce the output or would it cause damage?

Would it make a differnce if the tap into the supply was closer to the tank?

 

[Wayne County Hose]

For a 10 gpm pump, I would run 1" hose, especially for anything over 6" and not a straight shot. Basic rule of thumb, all sizes are figured off the pump outlet. Pump inlet hose is 2x pump pressure line, return is 1.5x pump pressure. I would not "tap" into the existing supply line. You'll end up starving both pumps. The closer you can bring the pump to the tank with the least amount of bends, the better. I also like T-bolt clamps for the suction line and good suction hose. Even better is 1 wire hose with crimp fittings.

As far as sharing fluid, it depends on the total capacity and any other fluid functions. Does the fluid also lube the tranny? This is really a gray area with much more info needed. Without seeing it, I would have to say install a separate tank to be on the safe side. I would also install a return filter, even if the tractor already has one.
Too small of a supply will cause pump cavitation and premature pump failure.

Hope this helps. Some other guys with more experience with this may be able to help you more.

And, no, if they outlaw guns, they will outlaw swords first. When going to practice or tournaments, I had to have my sword in it's scabbard and out of my reach from the drivers seat. That's the law. Try that in a Ford Ranger.

 

[Farmerford]

Mundy:

Wayne County Hose gave you good advice.

Pump cavitation occurs when the supply to the pump is restricted (due to small lines, long lines, clogged filter, etc.) and excessive vacuum (negative gauge pressure) is created at the pump inlet. Excessive vacuum causes tiny bubbles of air or water vapor to form in the fluid. When the bubble reaches the inlet of the pump and strikes the pump wall the pressure rises and the bubble collapses. The natural shape of the imploding bubble focuses the hydraulic fluid into a fast moving jet that strikes the pump wall with enough force to dislodge tiny bits of metal, much like the shaped charge used in antitank rockets. The precise vacuum at which this happens and the amount of damage caused depends on many factors, including some you might not expect, such as the finish (smoothness) of pump wall where the jet strikes. It is surprising (at least it was to me) that those tiny bubbles of normally harmless air in normally harmless hydraulic oil could do such damage, but I know from experience that they can. Indeed, in extreme cases they can destroy a pump housing or gear or impeller in an hour or less.

The rule of thumb for gear type pumps is to keep the vacuum at the pump inlet at or below 3 psi. For comparison, the vacuum in a typical automobile intake manifold is 12-14 psi. 3psi of vacuum will raise water only about 6 feet, so it is not a lot.

The actual vacuum at your pump depends on many factors, but the greatest are size of supply line, rate of flow, viscosity of hydraulic fluid, and fittings in the flow path. A 1" diameter hose five feet long with several elbows carrying 10 gpm of ISO 32 hydraulic fluid will result in a vacuum of between 1 and 2 psi when the fluid is warm (say 100 deg F or so). That's okay, but if you allow the 4 gpm TPH pump to share the supply line, the flow increases to 14 gpm and the vacuum at the pump inlet could rise to 3 psi or so.

All the above is just a guess based on what I think your situation is, but it confirms what Wayne County Hose knew off the top of his head. You need a separate supply line for the pump and it should be 1" ID, preferably with as few fittings and sharp bends as possible.

Surplus Center (among others) sells a cheap vacuum guage to mount at the pump inlet and I think it is redlined at 6" of mercury (which is about 3 psi). I would buy one of those just for peace of mind.

I have a wealth of experience on projects that seemed simple at first, but turned into a massive amount of work and expense for a very small benefit, and would have never been attempted had I known what was involved. This seems like one of those. There are lots of details that will eat time and money: the connector between the crankshaft pulley and the pump, the pump mount and a place to attach it, interference between the pump and FEL, fittings for the supply and return lines at the reservoir (particularly if you use the transmission as your sump), where to mount the return line filter.

It helps a little that I am partially deaf, but RPM's don't bother me like they did when I was young. Even before my hearing left I learned that RPM's, within reason, don't shorten engine life very much compared to other factors.

So if it were me, I would just turn it up to 2,750 rpm and not worry about it.

Good luck with your project.

 

[wedge40]

What kind of tractor are we talking about. I have a Ford 4000 and have been working on the same thing for a couple of years. I had a mount made to bolt the pump to the front of the tractor and got all the hardware to drive the pump off the engine. I also modified the front bumper so there is a second set of bars hooked to the tractor. Two bars running in parallel. It's on top of the bumper that I plan on putting the reservoir. With the pump just underneath it will be at most 12" from the tank to inlet. The tank will not be quite as big as recommended cause I've got a 15GPM pump and will be using a 10 Gal tank. But since I'm not going to be using it all day l I figure it should be fine. Just in case I'll install a temp gage to watch the fluid temp.

So far the hardest thing to figure out is all the connectors that go from the pump to what ever I'm going to drive.

Wedge

 

[Wayne County Hose]

Dang Farmerford, I bow to you!

 

[Mundy]

Thanks for the great response guys.
These are exactly the info I was looking for.

I see I will need a dedicated suction, but still think I will use the trans as my sump. I believe I can machine a spacer plate that will sit in between the existing suction line and the side of the trans and tap thru the side of the spacer to accept my new suction line. I attached a picture of the existing steel suction line and its connection to the trans. This port at the connection looks to be 1 1/2".


As for the connection to the the engine and mounting brackets I will fabricate what I need. I have lathe, mill, surface grinder, welders and a neighbor has a plasma cutter. I should be able to make anything I need in my shop.

I think I found a 11gpm pump including the coupler thing that goes in the middle of the shaft between the pump and the engine for near free today. I will be collecting other supplies over the next couple months.
I want to work out details first as this tractor is my snow mover and this will be a spring/summer project.


The tractor is a 1979 Satoh 370D.

 

[john_bud]

Can you mount a hydraulic tank off the front bumper? 5 gal would work.

What model FEL? Some of the old ones used the frame to hold the fluid.

jb

 

[Mundy]

I have seen the ones with the frame of the loader as the tank. Thats one of the slickest ideas I have seen.

The brand name of my loader is Blackhawk, I am told they were the OEM loaders on these tractors here in the US.
Being that the loader and tractor are 29 years old I do not think the inside of the loader frame is clean enough to be used as a tank.

I will have to do some measuring to see if a triangle shape tank will fit in front of the radiator. I am thinking I would have to fabricate a tank regardless of location.
Fabricating a tank is way more involved than machining a fitting to incorporate into the existing port in the side of the trans. With that port at 1 1/2" dia its area is just larger than the 2-1" lines it will feed.(if my math is right)


Another question: The pump I am looking at is 11GPM and the Inlet port is 3/4". Should I still feed it with 1" to make up for fittings and bends? Or would 3/4" be fine. The 3/4" would be easier for me to incorporate into the machined fitting.

 

[Wayne County Hose]

If the pump uses 3/4" inlet port, 3/4" hose should be okay. This will require a -6 or bigger pressure line and a -10 or larger return line. -10 is kind of a doggy hose, just go with -12. -12 will also make installing a return filter easy. I would probably run -8 from the pump to the valve, -6 from valve to cylinders.

You should look around at different tanks. They are made with all kinds of crazy shapes.