Adjustable gear pump?

[stevieb49829]

Ah, I think we're now getting a better picture of your setup. I think we're now just differing in our lingo. You're not really looking to 'adjust the pressure the pump is producing' (probably capable of oodles of pressure if you just consider the pump and no relief). Rather, I think you're looking to adjust the relief pressure at which the pump blows by the relief if something deadheads: Which will happen periodically in a steering system when you turn the wheel to full stroke and it dead-ends. In that case, you want to limit the pressure with a relief.

Or to say it differently: The way you first mentioned it, it sounded like you wanted to limit the pressure the pump was producing all the time. And our replies (simplified) were more-or-less saying "Well, you shouldn't really be producing any pressure most of the time". But if it's rather that it's just causing issue when deadheading (when fully stroked), then that's just a case of needing to blow by the relief in these occasionally deadheaded instances, which is a typical setup.

Do you have a link to the pump you bought? Some pumps have a built-in relief. Some are adjustable, some are not. And some pumps don't have any relief at all and expect the installer to have their own relief. If your pump has a relief but is not adjustable, I suspect it's factory set to something very high (like 3000-3500 psi), and it's expected your system has a second relief that's adjusted properly for the equipment you're running. If your pump doesn't have any relief built in, you need to add one down-stream of the pump. Otherwise you'll blow out seals and possibly do more damage, because with no relief and a deadheading instance, the pump will just keep building pressure until something blows or breaks.

Once again I'm guessing here, but if you say it only leaks occasionally, I'd bet dollars to buttons it's only leaking when you fully stroke the wheel and deadhead it for a second every now and again. In which case it just needs a lower relief setting. It doesn't sound like your pump has an adjustable relief (and might not have any relief at all). If it's one of the more basic, off-the-shelf gear pumps, it probably doesn't have any relief. So it's probably just a case of getting an off-the-shelf relief, plumbing it to your pump output, and dialing down the pressure. The relief will have three ports: one inlet, one outlet to your steering valve, and one outlet dumping to tank.

Something like this would probably be the ticket. Should be lots of places where you can buy one for less than $100: https://www.princessauto.com/en/adj...ImFmNBEM6magFIsBL3dA_ZNynadJ0SCRoCbLkQAvD_BwE

Thank You. That makes the most sense, since my pump doesn't appear to have a relief built in, and it could be only blowing past the seals when I'm occasionally at the stops on the steering. I will look it over more carefully though, and then I'll go looking for a separate relief valve. Can I assume my return to tank off a relief valve can be T'd into my return line from my orbital valve? That line is already oversized for what it has to flow, and it's in a convenient place. steve

 

[Janicholson]

Thank You. That makes the most sense, since my pump doesn't appear to have a relief built in, and it could be only blowing past the seals when I'm occasionally at the stops on the steering. I will look it over more carefully though, and then I'll go looking for a separate relief valve. Can I assume my return to tank off a relief valve can be T'd into my return line from my orbital valve? That line is already oversized for what it has to flow, and it's in a convenient place. steve

not the best because hot oil will be returned to get even hotter. Best is to rout it to the reservoir away from the tank supply to the pump.
Also it is fine to limit the total pump output pressure to the steering, if that is all there is being used. however a more "standard way to assure steering system viability is to use the priority valve already mentioned, as well as a max pressure relief. this would safely operate steering, and provide full reasonable pump pressure to any other use. (and if none are used, back to the reservoir unrestricted. My reasoning is that a pressure relief used as a fulltime limiter will force more oil through the steering valving and piping (which has limited flow capacity) and force the oil to flow through the pressure limiter much of the time causing heat. Jim

 

[wore out]

not the best because hot oil will be returned to get even hotter. Best is to rout it to the reservoir away from the tank supply to the pump.
Also it is fine to limit the total pump output pressure to the steering, if that is all there is being used. however a more "standard way to assure steering system viability is to use the priority valve already mentioned, as well as a max pressure relief. this would safely operate steering, and provide full reasonable pump pressure to any other use. (and if none are used, back to the reservoir unrestricted. My reasoning is that a pressure relief used as a fulltime limiter will force more oil through the steering valving and piping (which has limited flow capacity) and force the oil to flow through the pressure limiter much of the time causing heat. Jim

Many flow dividers used for tractor power steering have a relief valve built in eliminating the need for a separate component and associated plumbing.

 

[DanielW]

Thank You. That makes the most sense, since my pump doesn't appear to have a relief built in, and it could be only blowing past the seals when I'm occasionally at the stops on the steering. I will look it over more carefully though, and then I'll go looking for a separate relief valve. Can I assume my return to tank off a relief valve can be T'd into my return line from my orbital valve? That line is already oversized for what it has to flow, and it's in a convenient place. steve

For this application, I'd think you'd be fine to return into the same line -as long as it is truly oversized enough to handle the flow from both. For the very few (and short)instances that it's blowing by the relief, it should work just dandy plumbed like that. You shouldn't need much pressure nor flow for most steering systems. I'd dial back the relief to 1200 psi or so and see how it does from there.

Re: Janicholson's response of hot oil being returned to get even hotter: I don't think you have to worry about that for your setup where it's only blowing by the relief in the deadheaded instance when you stroke out the steering cylinder. I think he's assuming (like I did at first) that you're intending to limit the pump pressure by blowing over the relief almost constantly.

There still is a chance that, depending on your pump's size, it's producing way more GPM than your line and port sizing can handle and building excessive pressure that way. In which case a divider or priority valve might be warranted. But if it's the stock pump on that Massey (I'm assuming it's an MH30 if it's got the162 engine) and it's all external plumbing you've done yourself, I'd have a hard time believing it's producing enough flow to cause an issue on that newer orbital valve. But that's a bit of a guess. If you could find a priority flow divider with built-in-relief, that could be plumbed just like the relief, and would be an even safer bet. But you'd have to make sure it's relieving on the inlet side: It sounds like you need a relief on that system no matter what, so if you were relying on the relief of the priority valve to act as your primary relief, you'd want to make sure it was up to the task and relieving on the pressure port.

Is this the stock pump on that tractor? If so, how have you routed the lines? Do they run to anything else apart from the steering at any point (like remotes)?

 

[DanielW]

For this application, I'd think you'd be fine to return into the same line -as long as it is truly oversized enough to handle the flow from both. For the very few (and short)instances that it's blowing by the relief, it should work just dandy plumbed like that. You shouldn't need much pressure nor flow for most steering systems. I'd dial back the relief to 1200 psi or so and see how it does from there.

Re: Janicholson's response of hot oil being returned to get even hotter: I don't think you have to worry about that for your setup where it's only blowing by the relief in the deadheaded instance when you stroke out the steering cylinder. I think he's assuming (like I did at first) that you're intending to limit the pump pressure by blowing over the relief almost constantly.

There still is a chance that, depending on your pump's size, it's producing way more GPM than your line and port sizing can handle and building excessive pressure that way. In which case a divider or priority valve might be warranted. But if it's the stock pump on that Massey (I'm assuming it's an MH30 if it's got the162 engine) and it's all external plumbing you've done yourself, I'd have a hard time believing it's producing enough flow to cause an issue on that newer orbital valve. But that's a bit of a guess. If you could find a priority flow divider with built-in-relief, that could be plumbed just like the relief, and would be an even safer bet. But you'd have to make sure it's relieving on the inlet side: It sounds like you need a relief on that system no matter what, so if you were relying on the relief of the priority valve to act as your primary relief, you'd want to make sure it was up to the task and relieving on the pressure port.

Is this the stock pump on that tractor? If so, how have you routed the lines? Do they run to anything else apart from the steering at any point (like remotes)?

Further to my last reply, while doing some perusing I happened to find your post from 5 years ago where you talked about the surplus pump you put on it and posted a picture of it. A few more thoughts come to mind reading and looking at that old post:

- This is just a guess based off the picture on your old post, but I suspect the displacement of that pump is a little larger than what you might typically see on a tractor of that size/age. So there may be a little more chance the GPM is a concern and building pressure as it travels through the porting of your orbital valve. I'm a little doubtful that this is your main problem, however: Even if it is a (comparatively) high GPM pump, I don't think your porting would be restrictive enough to build significant pressure to cause the leakage you're seeing. It might build a little pressure and a little heat, but I think it would have to be a one heck of a large displacement pump and a very small orbital valve to cause the issues you're seeing.

- From the picture you posted, I don't think that pump has an in-built relief. I think this is then your primary problem: Every time you stroke-out and dead-end your steering you're likely pushing that pump to it's utmost limit and something's slipping/bypassing that shouldn't. I think you need to put a relief in there post-haste. With the current setup, at best you're bypassing and leaking through seals. At worst, you're going to lock up something and break a gear tooth or pump. There was a chap posting on here not long ago how dead-ended a pump on an Allis because of a bad relief. In his case, the hydraulic pump locked up and sheared teeth off the camshaft.

- You mentioned in that old post you were adding hydraulics for three-point. How have you plumbed this? Have you tee'd off the same pump pressure line somewhere and routed to the valve for the 3-pt? What type of valve do you have for the three-point control? Does it have its own built-in relief? If so (and if the pressure line is tee'd off the pump pressure line somewhere) that relief should/could act as your main relief, so you might try dialing it back a little.

- Again re: the 3-pt valve: I hope you're not taking the pressure for the 3-point system from the tank line on the orbital valve (essentially trying to run them in series - one valve feeding the next). That would also cause the issue you mention: If you did that, whenever you operated the 3-pt, the outlet port of the orbital valve (which is the one the shaft seals apply to) would be fully pressurized to whatever pressure the 3-point system needed to lift. That would/could definitely over-pressure the shaft seals and start leaking. For hydraulics run in series like that, you'd need to have power-beyond (high-pressure carry over) valves. Which your orbital valve is definitely not.

For a system like yours where the same pump is running steering, the 'proper' thing to do would be to use a priority flow divider. There's a safety reason for that: Theoretically, if something like your 3-pt demanded more flow and was a lighter load than your steering demands, the 3-pt could starve the steering for oil, and you'd lose steering. In your case for what looks like a higher(ish) GPM pump on an older tractor that's probably not seeing a boat-load of intensive 3-pt use, you'd probably never have that happen. Especially since it's only the three-point: It would only happen in the instance where you're steering at the same time as raising the three point and when the three-point load demanded less pressure than the steering. Knowing that you have a 2" cylinder for steering (fairly large for a small tractor like that), I think a lot of stars would have to align for that to ever be the case. But that's making some assumptions of your hydraulic routing and 3-pt usage.

Above all, it would be good to know how you're routed hydraulics to your 3-pt valve, and what type of valve it is.

 

[Jim.ME]

Further to my last reply, while doing some perusing I happened to find your post from 5 years ago where you talked about the surplus pump you put on it and posted a picture of it. A few more thoughts come to mind reading and looking at that old post:

- This is just a guess based off the picture on your old post, but I suspect the displacement of that pump is a little larger than what you might typically see on a tractor of that size/age. So there may be a little more chance the GPM is a concern and building pressure as it travels through the porting of your orbital valve. I'm a little doubtful that this is your main problem, however: Even if it is a (comparatively) high GPM pump, I don't think your porting would be restrictive enough to build significant pressure to cause the leakage you're seeing. It might build a little pressure and a little heat, but I think it would have to be a one heck of a large displacement pump and a very small orbital valve to cause the issues you're seeing.

- From the picture you posted, I don't think that pump has an in-built relief. I think this is then your primary problem: Every time you stroke-out and dead-end your steering you're likely pushing that pump to it's utmost limit and something's slipping/bypassing that shouldn't. I think you need to put a relief in there post-haste. With the current setup, at best you're bypassing and leaking through seals. At worst, you're going to lock up something and break a gear tooth or pump. There was a chap posting on here not long ago how dead-ended a pump on an Allis because of a bad relief. In his case, the hydraulic pump locked up and sheared teeth off the camshaft.

- You mentioned in that old post you were adding hydraulics for three-point. How have you plumbed this? Have you tee'd off the same pump pressure line somewhere and routed to the valve for the 3-pt? What type of valve do you have for the three-point control? Does it have its own built-in relief? If so (and if the pressure line is tee'd off the pump pressure line somewhere) that relief should/could act as your main relief, so you might try dialing it back a little.

- Again re: the 3-pt valve: I hope you're not taking the pressure for the 3-point system from the tank line on the orbital valve (essentially trying to run them in series - one valve feeding the next). That would also cause the issue you mention: If you did that, whenever you operated the 3-pt, the outlet port of the orbital valve (which is the one the shaft seals apply to) would be fully pressurized to whatever pressure the 3-point system needed to lift. That would/could definitely over-pressure the shaft seals and start leaking. For hydraulics run in series like that, you'd need to have power-beyond (high-pressure carry over) valves. Which your orbital valve is definitely not.

For a system like yours where the same pump is running steering, the 'proper' thing to do would be to use a priority flow divider. There's a safety reason for that: Theoretically, if something like your 3-pt demanded more flow and was a lighter load than your steering demands, the 3-pt could starve the steering for oil, and you'd lose steering. In your case for what looks like a higher(ish) GPM pump on an older tractor that's probably not seeing a boat-load of intensive 3-pt use, you'd probably never have that happen. Especially since it's only the three-point: It would only happen in the instance where you're steering at the same time as raising the three point and when the three-point load demanded less pressure than the steering. Knowing that you have a 2" cylinder for steering (fairly large for a small tractor like that), I think a lot of stars would have to align for that to ever be the case. But that's making some assumptions of your hydraulic routing and 3-pt usage.

Above all, it would be good to know how you're routed hydraulics to your 3-pt valve, and what type of valve it is.

From his reply in post #6 this is a dedicated pump for the power steering only. A plain old power steering pump and reservoir like Massey Ferguson (and others) used might be simpler in the end.

 

[stevieb49829]

Further to my last reply, while doing some perusing I happened to find your post from 5 years ago where you talked about the surplus pump you put on it and posted a picture of it. A few more thoughts come to mind reading and looking at that old post:

- This is just a guess based off the picture on your old post, but I suspect the displacement of that pump is a little larger than what you might typically see on a tractor of that size/age. So there may be a little more chance the GPM is a concern and building pressure as it travels through the porting of your orbital valve. I'm a little doubtful that this is your main problem, however: Even if it is a (comparatively) high GPM pump, I don't think your porting would be restrictive enough to build significant pressure to cause the leakage you're seeing. It might build a little pressure and a little heat, but I think it would have to be a one heck of a large displacement pump and a very small orbital valve to cause the issues you're seeing.

- From the picture you posted, I don't think that pump has an in-built relief. I think this is then your primary problem: Every time you stroke-out and dead-end your steering you're likely pushing that pump to it's utmost limit and something's slipping/bypassing that shouldn't. I think you need to put a relief in there post-haste. With the current setup, at best you're bypassing and leaking through seals. At worst, you're going to lock up something and break a gear tooth or pump. There was a chap posting on here not long ago how dead-ended a pump on an Allis because of a bad relief. In his case, the hydraulic pump locked up and sheared teeth off the camshaft.

- You mentioned in that old post you were adding hydraulics for three-point. How have you plumbed this? Have you tee'd off the same pump pressure line somewhere and routed to the valve for the 3-pt? What type of valve do you have for the three-point control? Does it have its own built-in relief? If so (and if the pressure line is tee'd off the pump pressure line somewhere) that relief should/could act as your main relief, so you might try dialing it back a little.

- Again re: the 3-pt valve: I hope you're not taking the pressure for the 3-point system from the tank line on the orbital valve (essentially trying to run them in series - one valve feeding the next). That would also cause the issue you mention: If you did that, whenever you operated the 3-pt, the outlet port of the orbital valve (which is the one the shaft seals apply to) would be fully pressurized to whatever pressure the 3-point system needed to lift. That would/could definitely over-pressure the shaft seals and start leaking. For hydraulics run in series like that, you'd need to have power-beyond (high-pressure carry over) valves. Which your orbital valve is definitely not.

For a system like yours where the same pump is running steering, the 'proper' thing to do would be to use a priority flow divider. There's a safety reason for that: Theoretically, if something like your 3-pt demanded more flow and was a lighter load than your steering demands, the 3-pt could starve the steering for oil, and you'd lose steering. In your case for what looks like a higher(ish) GPM pump on an older tractor that's probably not seeing a boat-load of intensive 3-pt use, you'd probably never have that happen. Especially since it's only the three-point: It would only happen in the instance where you're steering at the same time as raising the three point and when the three-point load demanded less pressure than the steering. Knowing that you have a 2" cylinder for steering (fairly large for a small tractor like that), I think a lot of stars would have to align for that to ever be the case. But that's making some assumptions of your hydraulic routing and 3-pt usage.

Above all, it would be good to know how you're routed hydraulics to your 3-pt valve, and what type of valve it is.

The 3 point now runs off the open center (power beyond) of my FEL dual spool valve, and has a crank-driven pump to supply this whole circuit of the FEL and 3Pt. Both the single valve for the 3 point and the dual spool have their separate returns to tank. I replumbed the smaller cam-driven pump that originally ran the 3 Pt to supply the power steering circuit. Both systems are completely autonomous, with their own reservoirs, and separate plumbing. steve

 

[moresmoke]

I may be assuming that the open center orbital valve is supposed to allow excess flow to return to tank. Does it have an adjustable flow bypass designed in? And it does not appear that my pump has any kind of adjustable flow control. It is just relying on a proper open center system to handle it. steve

The steering valve allows excess flow out the return until you hit the end of stroke on the cylinder. If you hold the wheel turned at the end of stroke you will deadhead the pump.

 

[stevieb49829]

The steering valve allows excess flow out the return until you hit the end of stroke on the cylinder. If you hold the wheel turned at the end of stroke you will deadhead the pump.

At which point the pump should be plumbed with a relief valve so it can't over-pressure the seals of the valve, right?

 

[moresmoke]

At which point the pump should be plumbed with a relief valve so it can't over-pressure the seals of the valve, right?

Not so much the seals, but you will have catastrophic failure somewhere if there is no relief.

 

[stevieb49829]

For this application, I'd think you'd be fine to return into the same line -as long as it is truly oversized enough to handle the flow from both. For the very few (and short)instances that it's blowing by the relief, it should work just dandy plumbed like that. You shouldn't need much pressure nor flow for most steering systems. I'd dial back the relief to 1200 psi or so and see how it does from there.

Re: Janicholson's response of hot oil being returned to get even hotter: I don't think you have to worry about that for your setup where it's only blowing by the relief in the deadheaded instance when you stroke out the steering cylinder. I think he's assuming (like I did at first) that you're intending to limit the pump pressure by blowing over the relief almost constantly.

There still is a chance that, depending on your pump's size, it's producing way more GPM than your line and port sizing can handle and building excessive pressure that way. In which case a divider or priority valve might be warranted. But if it's the stock pump on that Massey (I'm assuming it's an MH30 if it's got the162 engine) and it's all external plumbing you've done yourself, I'd have a hard time believing it's producing enough flow to cause an issue on that newer orbital valve. But that's a bit of a guess. If you could find a priority flow divider with built-in-relief, that could be plumbed just like the relief, and would be an even safer bet. But you'd have to make sure it's relieving on the inlet side: It sounds like you need a relief on that system no matter what, so if you were relying on the relief of the priority valve to act as your primary relief, you'd want to make sure it was up to the task and relieving on the pressure port.

Is this the stock pump on that tractor? If so, how have you routed the lines? Do they run to anything else apart from the steering at any point (like remotes)?

to answer the question: "Is this the stock pump on that tractor". Probably not. But it was made to fit where a magneto would go on this engine. I found it NOS at Surplus Center. It fit like a glove, and I've seen pictures of other Massey's of this vintage with a gear pump in this location. I finally found my info on the pump: 3.3 gpm @1500 rpm, 3000 psi max.

 

[stevieb49829]

error post

 

[moresmoke]

to answer the question: "Is this the stock pump on that tractor". Probably not. But it was made to fit where a magneto would go on this engine. I found it NOS at Surplus Center. It fit like a glove, and I've seen pictures of other Massey's of this vintage with a gear pump in this location. I finally found my info on the pump: 3.3 gpm @1500 rpm, 3000 psi max.

View attachment 119292

No relief valve in that pump, so yes you need one in the system. You will only get about 2.5 gpm with that pump in a tractor application.

 

[stevieb49829]

No relief valve in that pump, so yes you need one in the system. You will only get about 2.5 gpm with that pump in a tractor application.

Yah, I kind of figured it would be lower since I NEVER run the engine at 1500 rpms. I'll start my search for an appropriate relief valve. Gives me a good reason to return to my favorite scrap yard and poke around. Thanks for all your advice. steve