# Can someone help me understand this lift cylinder/pump?



## Perryd (Oct 16, 2020)

Hi everyone,

A bit of an oddball post here. I picked up an old plow today for doing my own driveway today with my SUV. I currently have a homemade, fixed angle plow that isn't too great (winch operated, not designed very well). The motor part number is STONE 1787-AC

Anyway it has an electric motor and pump combo, similar to what you see on a 2 post vehicle lift. This supposedly controls the single ram for lifting the chain which lifts the blade.

I don't know anything about snow plows so please help me out, but the pump has 2 outlets on it and the cylinder only has 1 inlet. Fluid only
Comes out of 1 side and it will extend the cylinder but not retract it. Even if I reverse the polarity of the electrical connections it will only expand, not retract the cylinder... the switch has up and down buttons. Up works but down does not, it just clicks, even if polarity is reversed. I'm stumped!!

Can someone please help me figure out how this thing works? I may not even have the right parts I just took the persons word. He did not believe the pumped worked, but it does if you bypass the relay that slides over some sort of shaft on the pump body.

So if your still reading, here is a video: https://streamable.com/w6wdlf

thanks so much!


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## Kinport (Jan 9, 2020)

That looks like a home built set up to me. Nothing wrong with that. I’m thinking The cylinder retract function is pressure activated, meaning when you click the “down” button on the plow, a valve opens and the dead weight of the plow pulls the plow down. Works off of gravity basically. It won’t drop for you because you have no weight on it. Get it mounted and put a plow on it and it should drop no problem. I think.


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## Perryd (Oct 16, 2020)

Thanks for the idea. You’ve got a point there. It’s not really possible to tell if it’s working right until it’s mounted.

If you listen in the video I posted you can hear the solenoid click rapidly if I hit the down button. Maybe it’s doing that because it needs presure to activate?

The only other experience I have with hydraulics is my auto lift. It uses a button to raise and a manual lever to release pressure. I’m just trying to understand how that down button can release the pressure!?


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## Kinport (Jan 9, 2020)

Ya I saw the smoke and sparks when you hit the down button- hard to say not seeing it but I’m wondering if you’ve got it wired correctly? Do you happen to have a picture of the moldboard part of the plow?


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## Randall Ave (Oct 29, 2014)

Need a few good stationary pictures of the pump, thought I saw a valve stem but no magnet on it. And that lift piston chrome looked darn rusty.


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## Perryd (Oct 16, 2020)

It’s past midnight here so I’ve called it a night out in the garage, but will post some good pics tomorrow.

i do believe it’s wired correctly. It’s only a 3 wire switch, it looks fairly simple. The cylinder is pretty nasty that for sure but it doesn’t seem to leak. Trying to give it a chance before I swap anything out or buy new parts.

thanks everyone, you’re all awesome!


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## TJS (Oct 22, 2003)

Yes post pics. There has to be a down valve. Albeit I do have an older liftgate pump (fenner) where the solenoids reverse the polarity of the motor so it is power up and power down. However I think your set up is just power up and gravity down.


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## cwren2472 (Aug 15, 2014)

Randall Ave said:


> Need a few good stationary pictures of the pump, thought I saw a valve stem but no magnet on it. And that lift piston chrome looked darn rusty.


You are correct - something definitely missing there


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## TJS (Oct 22, 2003)

Where you have that alligator clip at about 5 oclock in Cwren's screen shot you need the magnet part as Randell Ave has stated. Search Ebay for delta power and find a 12 volt one. That magnet when activated, activates the valve where you alligator clip is on that stem. This will let the fluid back into the reservoir. Also take that valve out and clean the valve and all the ports. That looks like a fenner pump most likely used for a dump bed.


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## Perryd (Oct 16, 2020)

The solenoid/relay that slides over the shaft to power the motor is bad. So you can see I jumped it in the pics.


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## cwren2472 (Aug 15, 2014)

This is a bit of speculation, but when it does come back down, fluid is going to want to come out the other exposed port since it's double acting. You will need a return hose from that back to the tank or at least plug that port


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## cwren2472 (Aug 15, 2014)

Perryd said:


> The solenoid/relay that slides over the shaft to power the motor is bad. So you can see I jumped it in the pics.


There is so much wrong in those two sentences, I seriously have no idea where to begin


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## Perryd (Oct 16, 2020)

Ok so if that relay/solenoid is operating correctly it will let the fluid return? This is the one I’m talking about.


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## cwren2472 (Aug 15, 2014)

K - lets start with some basics here.

#1) electric/hydraulic pumps like yours do not switch motor polarity to reverse operation. The motor always spins in the same direction and the fluid flow is controlled by the valve(s)

#2) the shaft you have that lead on is the valve that lets fluid return to the pump - the coil that slides over it is a magnet that when triggered makes the needle inside the valve move to change the flow of fluid. Jumping it like you do does nothing except short out the lead since the valve is grounded - hence the puff of smoke when you tried to lower it


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## Perryd (Oct 16, 2020)

cwren2472 said:


> K - lets start with some basics here.
> 
> #1) electric/hydraulic pumps like yours do not switch motor polarity to reverse operation. The motor always spins in the same direction and the fluid flow is controlled by the valve(s)
> 
> #2) the shaft you have that lead on is the valve that lets fluid return to the pump - the coil that slides over it is a magnet that when triggered makes the needle inside the valve move to change the flow of fluid. Jumping it like you do does nothing except short out the lead since the valve is grounded - hence the puff of smoke when you tried to lower it


Thank you!! So in order to test this I really do need the correct coil. Currently if installed the up button does nothing and the down button makes the main solenoid (one with battery leads) click rapidly.

I only jumped it because i wanted to make sure the motor worked as the person I got it from said it did not.


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## cwren2472 (Aug 15, 2014)

#3$


Perryd said:


> Thank you!! So in order to test this I really do need the correct coil. Currently if installed the up button does nothing and the down button makes the main solenoid (one with battery leads) click rapidly.
> 
> I only jumped it because i wanted to make sure the motor worked as the person I got it from said it did not.


Correct- without the coil and the valve working, it'll never lower.

The clicking is because the the way you connected it, it is shorting out causing the voltage to keep dropping so the solenoid can't work.

Because it's double acting, you will need to install some sort of diode in the wiring to keep the motor from trying to run when you are lowering it.


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## Perryd (Oct 16, 2020)

Ok this is starting to make sense. Thank you all so much for taking the time to educate me on how it works.

So, chances are this pump and plow lift were never originally together. Do you think I’d be better off getting a single-acting pump or is adding that diode a better solution?


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## cwren2472 (Aug 15, 2014)

Perryd said:


> Ok this is starting to make sense. Thank you all so much for taking the time to educate me on how it works.
> 
> So, chances are this pump and plow lift were never originally together. Do you think I'd be better off getting a single-acting pump or is adding that diode a better solution?


Correct - that pump was probably from a dump truck or the like. Any actual plow pump would have power angle functions built into it.

Depends what you mean by "better" - it would be simpler to just have the correct pump configuration to start with, but not cheaper. A new pump will likely run around $500.

A diode will only run a few bucks but will be more complicated to wire in.


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## cwren2472 (Aug 15, 2014)

Incidentally, I have no idea if the valve could have been damaged from the arcing of that lead - The valve is mechanical, not electrical, but the needle inside is pretty tiny and easily jammed/damaged. I have literally never heard of someone shorting it out as you did. So there is a chance it won't move even after getting the coil.


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## TJS (Oct 22, 2003)

After being able to see the vid from a different device. I see that it is for double acting. Not sure if a diode is needed for this. Maybe a simple momentary toggle with six terminals on the back. So when going up you are powering the motor and valve. The down would be wired without powering up the motor on the other side, but sending power to that valve/ magnet. However I still think you are going to have a plumbing issue cause your cylinder (for what I can see) only has one hose to it. You would have to experiment with the down part of it and just command the magnet/vavle and see if you have drainback. I am not a fan of those fenner stone (square magnet set up as they are known to go bad.). I replaced mine with a C (not sure of the letter) magnet from a Meyer. It has lasted for many years. You can get a new fenner stone valve body that is just for power up and gravity down but I would start looking for a gravity down complete set up. They are around used but you need to look around.


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## Randall Ave (Oct 29, 2014)

Three wire switch, power to the switch, then second wire is power to the motor solenoid, third wire is power to the valve magnet, which ain't there by the video.


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## Perryd (Oct 16, 2020)

Thanks for the replies everyone. Getting a gravity down setup certainly seems like the way to go but I will try some of the things suggested until I get my hands on one.

Nice to see such an active forum with no judgement for someone like me up doesn’t know up from down when it comes to this stuff.

I’ll follow up with whatever solution I end up finding.


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## cwren2472 (Aug 15, 2014)

TJS said:


> Not sure if a diode is needed for this. Maybe a simple momentary toggle with six terminals on the back. So when going up you are powering the motor and valve. The down would be wired without powering up the motor on the other side, but sending power to that valve/ magnet.


That's a great suggestion - much simpler than wiring a diode in.


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## Perryd (Oct 16, 2020)

Randall Ave said:


> Three wire switch, power to the switch, then second wire is power to the motor solenoid, third wire is power to the valve magnet, which ain't there by the video.


I have a 3 wire switch. I'm wondering if I have everything I need for this setup but my wiring is not correct? Or maybe main solenoid is bad? When I first put power to it main solenoid clicked rapidly in one direction on switch and did nothing on other direction. But in hindsight maybe the magnet coil was actually working But the motor was just jot getting power.
Will update later !


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## Randall Ave (Oct 29, 2014)

How bout showing us how you have it wired up, and like I asked, a few pictures of the pump, I think you are missing some items.


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## Perryd (Oct 16, 2020)

I have a few pics of the pump in the last page of the thread but I'll attach a few more. So now that I've hooked everything up the way I assume is correct the release valve shot fluid like 20 feet out the open port when I hit the the down button on controller. But the up button still rapidly clicks and smokes a bit when I press it. Here is another video as well. It does the same thing when I try cross the solenoid like you would trying to start an old car with a broken ignition switch. https://streamable.com/hi8maa


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## dieselss (Jan 3, 2008)

Whats the power supply your using to power this setup


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## TJS (Oct 22, 2003)

I don't see the switch you are mentioning that Randall has mentioned(a simple momentary toggle). I do still see the pendant. Your pics and vids are so close I cannot tell what is going on as a whole. Couple things come to mind. Low battery power. Bad main power solenoid or bad ground. How are you grounding this motor? In one of your pics there are two threaded blind holes which are 3/8-16 threads if I remember correctly. This is the mount for this thing. The ground terminal from the battery should be attached here. Also, why are you running this pump in the vertical position. Take the plastic reservoir off and you will see how the pump pickup is positioned in relation to the reservoir. Something could also be jammed in this pump. Don't continue to do what you are doing till you know the pump spins freely. When you take the reservoir off you will see the pump right there. Take the bolts out that hold it. There will be a splined coupler there when you pull the pump off the valve block as well as a figure 8 looking O ring. Don't loose them. Make sure the pump spins freely by turning the shaft with your hand. This also will give you a chance to clean all the muck up in that thing and see the orientation this unit should be in.


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## Perryd (Oct 16, 2020)

It’s a 12volt car battery that is good. So I think I have finally figured it out (maybe)

I bypassed the solenoid and got the pump to run. I’m used to starters and the like where the lug on the side is positive and the body of the motor negative. This is opposite.

as for the pump. It seems to me that the 2 fluid outlets both do the same thing.They both push out fluid with up button both release pressure when down-button is pressed (pump doesn’t run). It must have been from something that used 2 single acting cylinders.

i am going to try another good known battery before I try a new solenoid.


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## Perryd (Oct 16, 2020)

TJS said:


> I don't see the switch you are mentioning that Randall has mentioned(a simple momentary toggle). I do still see the pendant. Your pics and vids are so close I cannot tell what is going on as a whole. Couple things come to mind. Low battery power. Bad main power solenoid or bad ground. How are you grounding this motor? In one of your pics there are two threaded blind holes which are 3/8-16 threads if I remember correctly. This is the mount for this thing. The ground terminal from the battery should be attached here. Also, why are you running this pump in the vertical position. Take the plastic reservoir off and you will see how the pump pickup is positioned in relation to the reservoir. Something could also be jammed in this pump. Don't continue to do what you are doing till you know the pump spins freely. When you take the reservoir off you will see the pump right there. Take the bolts out that hold it. There will be a splined coupler there when you pull the pump off the valve block as well as a figure 8 looking O ring. Don't loose them. Make sure the pump spins freely by turning the shaft with your hand. This also will give you a chance to clean all the muck up in that thing and see the orientation this unit should be in.


thanks I'm going to take it apart tonight and get to know it better. How many volts and CCAs do I need to make it run. Would I need well above 12v like from a running motor?

you guys are so helpful thanks again!!


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## dieselss (Jan 3, 2008)

Perryd said:


> I bypassed the solenoid and got the pump to run. I'm used to starters and the like where the lug on the side is positive and the body of the motor negative. This is opposite.


WHAT? 
12v systems USUALLY use the case for ground or a stud on the case, and the copper stud in the back is the positive in.


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## Perryd (Oct 16, 2020)

dieselss said:


> WHAT?
> 12v systems USUALLY use the case for ground or a stud on the case, and the copper stud in the back is the positive in.


I know right!?!? Someone earlier in the thread mentioned polarity isn't relevant on this type of motor so if that's the case I'll be changing it back to positive stud and negative case. If I don't I've have to mount this thing in some type of rubber bucket because if it fell off or rubbed it would go BOOM lol.

that is if I'm looking at it correctly. Which may not be the case given how ignorant to how these work I am.. hah


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## TJS (Oct 22, 2003)

You misinterpreted the polarity comments. Go back and read them again.
As Crewen stated your motor only spins one way. As I stated I have an older tailgate lift pump where there are TWO SOLENOIDS that change the polarity. Your set up only has one solenoid. I also stated the negative terminal from the battery needs to be where these pumps mount provisions are which is the 2 threaded holes about 4 inches apart in one of your pics. That takes 3/8-16 bolts.


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## Perryd (Oct 16, 2020)

Ok guys... I feel so stupid.. my god.

so I finally hooked the dang jumper cables up where they are supposed to go and the switch wires as pictured and it runs perfect with the press of a button and also releases pressure with the other.

only thing is the pump pushes out one outlet that I have the line on and then releases it out the other side. I’m not sure what this will be like in reality, like perhaps it could be plugged and then the fluid will flow back into to the reservoir instead?

I’ll really have to mount the plow and play with it a bit to really see how it works because right now there is no weight to collapse the ram.


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## cwren2472 (Aug 15, 2014)

Perryd said:


> only thing is the pump pushes out one outlet that I have the line on and then releases it out the other side. I'm not sure what this will be like in reality, like perhaps it could be plugged and then the fluid will flow back into to the reservoir instead?


Correct - that is what I said earlier would happen. That is normal operation since it is designed for a 2 port cylinder where the fluid would push to the other end. I believe that you can just plug it and it should work ok but I'm not 100% positive. Worst case, you'd need a hose going from that port back to the tank.


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## Perryd (Oct 16, 2020)

Sorry I never really understood what you were saying until I had some more time to look at the pump. I thought about the hose going to tank as well, glad to know you think it’s an opinion. Thanks for your help and patience and I will update you all when I get the plow mounted. I think it’s going to work! The person I got it from said the motor was no good, I guess it was just a lose wire or dirt/corrosion by those 3/8 bolts you mentioned ( it was very dirty) . It think they just had some of the wires messed up!


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## Randall Ave (Oct 29, 2014)

cwren2472 said:


> Correct - that is what I said earlier would happen. That is normal operation since it is designed for a 2 port cylinder where the fluid would push to the other end. I believe that you can just plug it and it should work ok but I'm not 100% positive. Worst case, you'd need a hose going from that port back to the tank.


I think he can plug that other port, as long as his tank has a breather. Which it should.


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## Perryd (Oct 16, 2020)

Thanks again to everyone for all the replies. As Randall Ave mentioned a plug in the other port did the trick. It all works perfectly as it should, leak free! Just need to mount the pump on the plow frame (no space under the hood) and run a wire for (+) power and I'm all good!

https://streamable.com/xd84rd


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