# Hydraulic system loads and upgrades



## Bucky533 (12 d ago)

Howdy yall, got a sparky here with no knowledge of hydraulics and new to tractors. I'm trying to understand how to know if/what your tractor (lawn tractor in my case) is capable of performing with its hydraulic system. I'm used to Electric where you start with the load to determine ampacity, wire size, breaker size etc... is this similar with hydraulics? If I determine my hydraulic setup on my tractor is undersized for my needs, is it possible to increase? I believe I also read that the hydrostatic tranny on my tractor is ran off the same hydraulic system, so I assume this would take away from the capacity? Any info on the subject is much appreciated!


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## sixbales (May 18, 2011)

Howdy Bucky, welcome to the forum.

It would help if you stated what you want to do that requires additional hydraulics. For example, if you want to lift a snow plow or snow blower, you might consider using an electric lift??


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## BinVa (Sep 21, 2020)

Welcome to the forum. 
What tractor/loader are you working with? You should be able to find the published specs. for your loader. That will tell you what it's potentiall is. Tho that may be limited by the tractor weighting and balance. And general condition of the tractor/loader mounts, frame and front wheel/axle. B.


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## Vigo (Oct 8, 2021)

It really depends what you’re starting with. Nearly all ride-on mowers use ‘hydrostatic’ transaxles that include a variable displacement hydraulic pump hooked to a fixed displacement hydraulic motor, but you cannot tap into this flow for external hydraulics. Some older ‘garden tractor’ hydrostatic transmissions did have a separate (but still internal to the hydrostat) pump which could power external hydraulic attachments, but pressure was a little low and flow was ‘a lot’ low, so the external attachments needed to be designed with that hydraulic ‘source’ in mind or they would be extremely slow.

So it really depends what you’re starting with. But, it bears stating that if it has an engine you can add a hydraulic pump to it!


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## Bucky533 (12 d ago)

sixbales said:


> Howdy Bucky,
> 
> 
> sixbales said:
> ...


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## Bucky533 (12 d ago)

Vigo said:


> It really depends what you’re starting with. Nearly all ride-on mowers use ‘hydrostatic’ transaxles that include a variable displacement hydraulic pump hooked to a fixed displacement hydraulic motor, but you cannot tap into this flow for external hydraulics. Some older ‘garden tractor’ hydrostatic transmissions did have a separate (but still internal to the hydrostat) pump which could power external hydraulic attachments, but pressure was a little low and flow was ‘a lot’ low, so the external attachments needed to be designed with that hydraic ‘source’ in mind or they would be extremely slow.
> 
> So it really depends what you’re starting with. But, it bears stating that if it has an engine you can add a hydraulic pump to it!


Thanks for the info! I just bought a kubota F2000. Basically trying to make a poor man's Steiner and fab up my own attachments to the front. It came with the mower deck, snow blower, and plow. I'd like to make a small tiller and slip scoop bucket for it. I just don't know how to find the info for what my tractor can handle, as well as what the implements would demand.


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## Vigo (Oct 8, 2021)

Well that’s great news that it’s an F2000. Mowers like that are more like tractors than theu are like other kinds of mowers. For example, i poked around on Messick’s website parts catalog and when you look up the number for the HST trans it says it fits 12 models, expanded that list and found that it uses the same hydrostatic transmission as a B1550, B1750, B6200, and B7200. So in terms of durability the HST should he able to push and pull fairly hard, although i dont know the details of the gearing between the HST and tires so you are probably ‘in high range all the time’ compared to those tractors which have a low range as well. 

Messicks parts catalog also shows that the engine already has a hydraulic pump on it (im guessing this machine has hydraulic deck lift and power steering?) and it is the same pump used on a B6100 or B7100. I dont know how to find GPM from Messicks website but if you look up a B7100 on Tractordata.com it is a 3gpm pump. 

So that’s an example of my research process using those two websites which are great resources. 

Anyway, 3gpm sucks. You can certainly move a cylinder with it (preferably only one, if you try to run two cylinders in parallel such as an FEL it will be very slow) but it’s not enough to run a hydraulic motor of any decent speed/torque combo. If all you’re trying to do is lift/lower/angle functions which each have only one reapsnably sized cylinder, it will be fine. 

The bucket would be fine. They don’t need a lot of flow. If you wanted to operate a tiller with a hydraulic motor on it you would need to install a larger hydraulic pump somewhere on your machine. There are many options for that. If you have to build half the tiller attachment anyway to get it to mount to your machine, you may just consider running it with a self-contained side shaft engine rather than jump through the hoops for upgraded hydraulics. My .02. 

Anyway, cool machine and cool ideas. Id sure like to see pics of whatever you build.


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## Bucky533 (12 d ago)

Vigo said:


> Well that’s great news that it’s an F2000. Mowers like that are more like tractors than theu are like other kinds of mowers. For example, i poked around on Messick’s website parts catalog and when you look up the number for the HST trans it says it fits 12 models, expanded that list and found that it uses the same hydrostatic transmission as a B1550, B1750, B6200, and B7200. So in terms of durability the HST should he able to push and pull fairly hard, although i dont know the details of the gearing between the HST and tires so you are probably ‘in high range all the time’ compared to those tractors which have a low range as well.
> 
> Messicks parts catalog also shows that the engine already has a hydraulic pump on it (im guessing this machine has hydraulic deck lift and power steering?) and it is the same pump used on a B6100 or B7100. I dont know how to find GPM from Messicks website but if you look up a B7100 on Tractordata.com it is a 3gpm pump.
> 
> ...


Thank you for those examples, that's actually really helpful. The tractor does have a pto shaft coming out the front so that was my plan to turn parts such as the tiller. So the hydraulics would be mainly for llifting. I'm glad to know that I CAN upgrade the hydraulics of needed, but at that point I might just buy another tractor 😁. Thanks for your input, I'll definitely post pics once I get something going!


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## Busted Tractor (May 22, 2018)

Hydraulics compared to electric: Pressure = Voltage Flow = amperage
Basic hydraulics is simple a reservoir holds the fluid, a pump moves the fluid, a valve controls the fluid, a cylinder or motor does the work. All connected by tubing or hoses.
Some critical specs. size of pump determines speed of cylinder or motor speed. Pumps are open center or closed center. Open center MUST have a relief valve as the pump is positive displacement and something will break if the pump is turning and flow stops. Closed center oil flow stops by the system maintains high pressure (think of the water system in your house)
Pump do mot make pressure, the load or a restriction does. A valve send the oil to the reservoir or the work, most do not have internal o rings, only O rings to keep the oil in.
A low GPM pump with a large cylinder = slow movement. A high GPM pump and a small cylinder = fast movement

Here are some sites that might help you understand the basics






Basic Hydraulic Theory | Cross Mfg.


Hydraulic systems is expressed by Pascal's law. In a basic circuit, the force exerted by a cylinder is dependent on the cylinder bore size and pump pressur




crossmfg.com













Hydraulic Basics


Learn about Fluid Power Basics with this Hydraulics Lesson. LunchBox Sessions is a new take on online industrial training, full of interactivity, used by individuals, schools, and companies around the world.




www.lunchboxsessions.com


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## Vigo (Oct 8, 2021)

Re: the shaft-driven tiller.. i suspect yoy will find it may be easier to add a new hydraulic pump than to make the existing driveshaft directy spin a tiller. Im basing this on the assumption that the pto shaft probably spins somewhere around 1000-2000 rpm depending on engine speed, so if you took an existing 540rpm tiller and adapted it you’d need to swap the gearbox or add an additional reduction inline. Some tillers originally intended for garden tractors had faster pto speeds that would be ‘plug and play’ with your shaft rpm but they’d likely be pretty small compared to the rest of your machine.

I think if i was in your shoes trying to build a powered attachment, i may still go with hydraulics just for the relative ease of changing the speed and axis of the power you’re trying to transfer, but if it was only going to be one ‘motor’ type attachment id just leave all the hydraulics on the attachment! A pump on the attachment that your pto shaft would hook to, and some hoses over to a hydraulic motor. The relative displacements of those two pieces lets you pick any ‘ratio’ between your pto shaft rpm and the rpm of the attachment’s driven shaft. The parts cost money but so do gearboxes, chains/sprockets etc but there are no alignment or wear issues to speak of compared to a physical driveline.

Also i noticed on Tractordata that the mower DOES have a low range. That’s cool!


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## Bucky533 (12 d ago)

Thanks everyone for sharing, all comments were very helpful! I feel like I have some basic knowledge to start with now. I will post some pics when I can put it to use!


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