B7200 hydraulic steering

[Paul Allwood]

I'm in the process of purchasing some hydraulic steering bits from a BX from Daryl at Mossy Creek Outdoors @Mountainman - planning to attempt to fit it to my B7200 HSTD 4WD hydrostatic.

I found the plumbing diagram below on another thread - I think it was done by @North Idaho Wolfman - apologies if I have that wrong.

The specified maximum hydraulic oil flow rate is 15 l/min.

Would this plumbing work in my case ?

Is the line out of the steering control valve to the PB/T a pressure line suitable for supplying the FEL valve ?

Many thanks as always.

 

[North Idaho Wolfman]

No you can not do that, there are several reasons, but #1 is that the PS controller can not handle the volume required to run the rest of the systems properly.
Have him send you a priority valve to split the flow into 2 paths.

 

[Paul Allwood]

@Mountainman - can you also help with this as suggested above by NIW ? I'll add it to the emails.

 

[Paul Allwood]

No you can not do that, there are several reasons, but #1 is that the PS controller can not handle the volume required to run the rest of the systems properly.
Have him send you a priority valve to split the flow into 2 paths.

View attachment 169394

Ok, thanks heaps.

I'll have a go at a plumbing diagram and post it for critique.

 

[TheOldHokie]

Ok, thanks heaps.

I'll have a go at a plumbing diagram and post it for critique.

Its just a prority flow divider that duvides one input stream (pump) into two separate outlet steams. One outlet has priority and gets a fixed flow for the PS circuit. Excess flow, if any, goes to the implement circuit.

Therein lies your problem. Your pump produces a 4 GPM flow at max RPM and if you suck off anything close to 15 LPM for the PS circuit there will be nothing left for the implement circuit. What you need is an additional pump for the PS and forget about a priority flow divider.

Dan

 

[Paul Allwood]

Its just a prority flow divider that duvides one input stream (pump) into two separate outlet steams. One outlet has priority and gets a fixed flow for the PS circuit. Excess flow, if any, goes to the implement circuit.

Therein lies your problem. Your pump produces a 4 GPM flow at max RPM and if you suck off anything close to 15 LPM for the PS circuit there will be nothing left for the implement circuit. What you need is an additional pump for the PS and forget about a priority flow divider.

Dan

Thanks Dan.

 

[Paul Allwood]

Well, this leaves me in a difficult spot of not really knowing what to do. I've only been a member of OTT for about 6 months with no previous experience with tractors or hydraulics. I've got two different opinions on which path to take from two of this site's respected experts, @TheOldHokie and @North Idaho Wolfman and I'm in no position to pretend to be able to argue with either of you.

Dan, NIW - is there anything you can offer to help clear the path ?

Many thanks both.

 

[Russell King]

@Paul Allwood
Not that you asked me but here is my opinion on your situation.

1) NIW was probably focused on the system requirements of a priority flow divider and never considered how much GPM that your tractor hydraulic pump can produce. So he just pointed out that you need the priority flow divider.

2) The Old Hokie probably has the manual for your tractor that states what the hydraulic pump flow is. I also assume he knows how much flow the BX steering system requires in a similar manner. So he is warning you that you can’t use the tractor pump to do both steering and implements. He suggested separate systems to resolve your issue and still have power steering and be able to use your implements.

I suggest you confirm how many liters per minute your tractor can produce and also how many liters per minute the power steering system requires. Then you can see the dilemma yourself and decide how to proceed.

As I see it you have three options:
1) Abandon the plan for power steering.
2) Provide a separate pump that will satisfy flow for the power steering.
3) Change to a different type of power steering that doesn’t require as much flow.

You can mount a hydraulic pump that is driven off the front of the tractor crankshaft or driven by a belt.

You can see the belt driven pump style and a priority divider valve in this thread as well as an older type of power steering system that was used on a tractor that was produced in the same era as your tractor (I may be wrong on years of production).

Rear remote hydraulic on Kubota L245DT

My L245DT has aftermarket power steering..does not have a front end loader. The power steering cylinder is connected to the control valve below the left side of the seat via an aluminum block. How do I do this? Thanks for any help.

www.orangetractortalks.com

And I apologize in advance for butting in!

 

[Russell King]

And I forgot to mention that the separate pump might be able to be used for the FEL (which I think you added) but that would require the use of a priority flow divider valve.

 

[Paul Allwood]

@Paul Allwood
Not that you asked me but here is my opinion on your situation.

1) NIW was probably focused on the system requirements of a priority flow divider and never considered how much GPM that your tractor hydraulic pump can produce. So he just pointed out that you need the priority flow divider.

2) The Old Hokie probably has the manual for your tractor that states what the hydraulic pump flow is. I also assume he knows how much flow the BX steering system requires in a similar manner. So he is warning you that you can’t use the tractor pump to do both steering and implements. He suggested separate systems to resolve your issue and still have power steering and be able to use your implements.

I suggest you confirm how many liters per minute your tractor can produce and also how many liters per minute the power steering system requires. Then you can see the dilemma yourself and decide how to proceed.

As I see it you have three options:
1) Abandon the plan for power steering.
2) Provide a separate pump that will satisfy flow for the power steering.
3) Change to a different type of power steering that doesn’t require as much flow.

You can mount a hydraulic pump that is driven off the front of the tractor crankshaft or driven by a belt.

You can see the belt driven pump style and a priority divider valve in this thread as well as an older type of power steering system that was used on a tractor that was produced in the same era as your tractor (I may be wrong on years of production).

Rear remote hydraulic on Kubota L245DT

My L245DT has aftermarket power steering..does not have a front end loader. The power steering cylinder is connected to the control valve below the left side of the seat via an aluminum block. How do I do this? Thanks for any help.

www.orangetractortalks.com

And I apologize in advance for butting in!

Many thanks Russell. I don't think I'd like to assume what anyone did or didn't take into account here, but all input is most welcome.

 

[TheOldHokie]

Many thanks Russell. I don't think I'd like to assume what anyone did or didn't take into account here, but all input is most welcome.

You dont have to assume anything.

Do you understand what a priority flow divider does and why they are used to provide a PS circuit? Thats what NIW was hinting at.

I simply pointed out that in your specific situation that solution is problematic due to the low flow rate of your hydraulic pump and the flow requirements of your loader.

Kubota offered a factory PS option for the B7200. It used a priorty fkow divider placed between the pump and hydraulic outlet block . It stole flow from the aux and 3pt circuit and the negative effect of that on a loader is unambiguous. That may be why very few B7200 tractors had factory PS.

Kubota has moved away from using flow dividers and now favors tandem pumps with one section supplying a steering circuit and the other suppkying the implement circuit.

Your options are pretty limited.

1. Use your original circuit and live with the problems inherent in it.
2. Add a flow divider and live with the problems inherent in it
3. Retrofit an EPS type system and live with the added stress a loader puts on the woefully fragile steering box.
4. Forget about power steering and live with heavy steering and the same steering box problem inherent in (3).
5. Add a second pump and avoid all of the problems above.

Dan

 

[mdhughes]

I found this on the web B7200 power steering, don't know if has anything to do with your tractor.

 

[TheOldHokie]

I found this on the web B7200 power steering, don't know if has anything to do with your tractor.

That is the parts breakdown of the B7200 factory power steering option. Very nearly a Unicorn and suffered from the insufficient flow problems I described earlier.

Dan

 

[Paul Allwood]

You dont have to assume anything.

Do you understand what a priority flow divider does and why they are used to provide a PS circuit? Thats what NIW was hinting at.

I simply pointed out that in your specific situation that solution is problematic due to the low flow rate of your hydraulic pump and the flow requirements of your loader.

Kubota offered a factory PS option for the B7200. It used a priorty fkow divider placed between the pump and hydraulic outlet block . It stole flow from the aux and 3pt circuit and the negative effect of that on a loader is unambiguous. That may be why very few B7200 tractors had factory PS.

Kubota has moved away from using flow dividers and now favors tandem pumps with one section supplying a steering circuit and the other suppkying the implement circuit.

Your options are pretty limited.

1. Use your original circuit and live with the problems inherent in it.
2. Add a flow divider and live with the problems inherent in it
3. Retrofit an EPS type system and live with the added stress a loader puts on the woefully fragile steering box.
4. Forget about power steering and live with heavy steering and the same steering box problem inherent in (3).
5. Add a second pump and avoid all of the problems above.

Dan

Many thanks Dan.

It's looking like it's hard to go past option 5 above. I assume an automotive style power steering pump would work (since they work in cars), and they will be easy to source.

My understanding of priority flow divider valves is limited to what I've picked up in this thread - so it's not much. Probably more questions than answers.

 

[TheOldHokie]

Many thanks Dan.

It's looking like it's hard to go past option 5 above. I assume an automotive style power steering pump would work (since they work in cars), and they will be easy to source.

My understanding of priority flow divider valves is limited to what I've picked up in this thread - so it's not much. Probably more questions than answers.

Option (1) "works" but you have the steering in series eith the loader and 3pt. The problem with that is when you operate the loader you lose power steering assist

Having owned a B7200DT I think a front mounted crankshaft driven pump is the easiest way to add a second pump.

Dan

 

[TheOldHokie]

Many thanks Dan.

It's looking like it's hard to go past option 5 above. I assume an automotive style power steering pump would work (since they work in cars), and they will be easy to source.

My understanding of priority flow divider valves is limited to what I've picked up in this thread - so it's not much. Probably more questions than answers.

This is from the BX1880 WSM and shows how the power steering circuit is implemented.

1. Item (3) is the priority flow divider which takes the full output of the hydraulic pump (max of 5.5 GPM) and divides it into two separate supplies
2. The priority stream is a constant 1.8 GPM flow and is sent to the steering controller
3. The excess stream is whatever is leftover after the 1.8 GPM is diverted from the pump supply. It is sent to the loader outlet block and from there to the 3pt control valve.
4. Simple arithmetic tells us the maximum flow going to the loader is 3.7 GPM which is pretty close to the max your B7200 pump can produce.
5. The pump on your B7200 can only produce ~3.9 GPM so using a flow divider and this PS controller on your tractor reduces the max loader supply to 3.9 - 1.8 = 2.1 GPM. Its going to be about half as fast as it is now.

Does that help your understanding of prority flow dividers any?

Dan

 

[Paul Allwood]

This is from the BX1880 WSM and shows how the power steering circuit is implemented.

View attachment 169471

1. Item (3) is the priority flow divider which takes the full output of the hydraulic pump (max of 5.5 GPM) and divides it into two separate supplies
2. The priority stream is a constant 1.8 GPM flow and is sent to the steering controller
3. The excess stream is whatever is leftover after the 1.8 GPM is diverted from the pump supply. It is sent to the loader outlet block and from there to the 3pt control valve.
4. Simple arithmetic tells us the maximum flow going to the loader is 3.7 GPM which is pretty close to the max your B7200 pump can produce.
5. The pump on your B7200 can only produce ~3.9 GPM so using a flow divider and this PS controller on your tractor reduces the max loader supply to 3.9 - 1.8 = 2.1 GPM. Its going to be about half as fast as it is now.

Does that help your understanding of prority flow dividers any?

Dan

Thanks Dan. Yes, it does. I was wondering if there priority valve always takes the steering flow even when there is no steering happening - this makes it clear.