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npalen

Power Steering Question

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npalen
[url]http://www.tractorpowersteering.com/cylinders.php[/url] Wondering if anyone has done a PS retro on an Allis 720/Powermax using this type of cylinder with integral valve? My concern is space especially with a FEL. I'm interested in this approach due to cost and complexity of the torque multiplier type of retro. Thanks Nelson

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D-17_Dave
Currently out of stock doesn't sound promising. Where do you plan on getting your oil flow from? The picture is pretty self explanatory but it doesn't show the oil flow circuit. Without power beyond you'll soon blow the valve body out.

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npalen
Some guys use a flow divider for that purpose or a power beyond valve. In my case I would use the charge pump output to run the steering. A selector valve would then switch the loader pump output between the loader and the 3PH.

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D-17_Dave
OK, if you divert all the charge pump output to just the PS setup you'll likely be OK. If you use a control valve for the loader with power beyond you won't need the selector or the flow divider. Just remember the relief valve in the loader valve will likely be set higher than the lift valve in the tractor. This is OK and needs to be this way as the lift and cylinders on the tractor aren't designed to handle the higher pressure of an external system so it's very important to limit what goes to the tractor's system. The flow on the tractors system could be an issue though. It's not plumbed to handle much past 7-8 gpm. You may have to limit the throttle or size pump on the loader.

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npalen
Dave, I like your idea of the power beyond on the loader valve. That would be a lot handier than having to switch a selector valve to go between loader and 3PH functions. I'm trying to visualize what happens if the loader pump output exceeds the capacity of the tractor circuit for the 3PH and the auxiliary remote. Would the excess fluid go past the relief on the tractor valve or would the pump drive belt have to slip or worse? With that said, I doubt that the loader pump puts out more than 7-8GPM even at full throttle but don't know that for sure. Thanks for your help. Nelson

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D-17_Dave
In any oil flow circuit the system only builds pressure when you restrict the oil flow. Such as when you divert the flow to do work, like when you stroke a cyl. under load. The problem is a certain appliance (valve) with sized fittings for the designed circuit are rated to only flow so much. You can do things like make sure all the fittings are sized up and match the new desired oil flow. This works as long as the appliance is rated as high as the new circuit. If you restrict the oil flow at any point in the circuit you'll create "work" for the oil and build heat. It will be the creation of heat that could lead to the destruction of any number of components in the system. It will be impossible to know what the target is unless you have some data to judge it all by. The place to start is of course the pump. Even if a pump is rated at so much flow at so many rpms, you still need to know as close to reality what your flowing at max rpm. You can only see this by using a flow meter. If you know exactly what you have in flow you can figure out most of the rest of the circuit in hose and fitting size.

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npalen
Thinking about this some more, guys: Wondering what it would take to jury rig a steering cylinder by mounting a 4-way directional valve on a cylinder? What would the requirements be for that valve? Compact size/low flow? Open center with blocked cylinder ports? A spool override to allow manual steering in event of pressure loss? Anyone know what's inside these steering servo valves? Thanks Nelson

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D-17_Dave
The rotory steering valves use a series of metering plates and counter springs to allow for finite amounts of flow control to regulate the flow of oil to a cyl. This keeps the steering from being jerky. The rotory valves are also designed to act as a pump so you still have steering if you loose hydraulic flow.

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npalen
Dave It's interesting trying to relate what you're saying about the rotary valve to a linear. I would think that the spool would definitely need to be spring centered. Not sure how one would accomplish the manual steering. Seems like the spool would need to have an "extreme position" that would block the A and B cylinder ports for manual mode. Would love to see a cutaway of one of the valves. Nelson

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D-17_Dave
If your bent on using a spool valve then get one with float, that will take care of opening both ports for manual steering. MOST spool valves are designed for full flow when you stroke the spool, this would make the steering so fast you wouldn't be able to control the steering for small corrections. Hence the reason for the rotory metering valve.

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npalen
Dave--I'm not bent on using anything. Just wanting to discuss what's involved in power steering systems and what might be available for those of us without a lot of discretionary income. I don't see the spool stroking full open unless you turned the steering wheel quickly but rather only "cracking" with light pressure on the steering input. "Some" spool valves have grooves cut into the spool lands to soften the transition. That might be a a simple modification to a valve. There may be a problem using a conventional spool valve, however, in that input from the wheels when hitting a rut might create a violent "dithering" action. What do you think? Nelson

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acfarmer
Be interested in what you come up with,I just bought a 4040 with a loader and thinking about power steering.I have a parts Sunstar with power steering so I might just move all that over.

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RBE17
quote:
Originally posted by acfarmer
Be interested in what you come up with,I just bought a 4040 with a loader and thinking about power steering.I have a parts Sunstar with power steering so I might just move all that over.
That's what I decided to do. I didn't do it yet, but I bought all the parts from Sandy Lake to put on my 9020. I don't know very much about hydraulics and decided the design work was done. All I have to do is make it fit.

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D-17_Dave
Best bet is to obtain a parts tractor like Gary did and modify the parts to work. This is in essence what I did on my first conversion. If you look it up in the archives you should find it. It works very well but does require some cutting and welding. I also just finished a torque amplifier type PS conversion on mu 9020. I like it so far but still have to put it through the working paces of mowing. I should do that next week. You won't get the shuddering bounce effect when you strike an object. You'll likely tear the front axle off if you apply too much force from the hydraulics against what you hit. I won't say you can't use a spool valve, I will say you won't be happy with the results. That's why they made the rotory steering valves.

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RBE17
quote:
Originally posted by npalen
Does Sandy Lake have the parts available as a kit or as individual parts? I would be interested if you can point me there. Thanks Nelson
Nelson, I just called Brenda and asked them if they had a Sunstar parts machine. I told her I'd be interested in purchasing all the power steering parts to retrofit onto my 9020. She talked to Bill and now I have them. Give them a call, I'm sure they'll work w/ you. I had Dave's ps build bookmarked, but now it's gone.CCC If I'm able to find it, I'll post it for you.

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npalen
I would love to have Dave's setup. It's the ultimate as far as I'm concerned. This thread is what got me to thinking about the cylinder with integral valve. The final product is is the lower left hand picture. [url]http://www.tractorbynet.com/forums/customization/138014-power-steering-90-minutes.html[/url] (Hope is okay to post a link to another site) Nelson

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npalen
[url]http://www.simpletractors.com/club2/topic.asp?ARCHIVE=true&TOPIC_ID=98507&SearchTerms=power%2Bsteering[/url] This thread has some info on this type of power steering showing what the valve looks like inside as well as the cylinder. I believe this is on a Deutz Allis diesel and wondering if it would be the same as used on the Sunstar power steering? Thanks Nelson

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CarlH
That is the early power steering setup for Sovereigns. The later Sovereign power steering uses the same major components as a Sunstar.

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npalen
Thanks, Carl. Can you or someone point me to info on the Sunstar PS? I'm looking to retrofit the Sunstar PS to an Allis 720 and wondering what the system components look like. Nelson

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npalen
[url]http://www.simpletractors.com/club2/topic.asp?ARCHIVE=true&TOPIC_ID=83232&SearchTerms=sunstar,steering[/url] Looks like I found it?

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CarlH
Service and parts manuals for both Sovereigns and Sunstars have information and illustrations. Parts manuals can be found on the Simplicity website.

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