I dont know which sleeve i need but the one i have, stays at bottom until pump comes on then spring compresses and sleeve goes up into upper chamber where it lets fluid go into the power beyond and upper section thats where i've got the problem but was wondering if i was to keep it at bottom would that let it work properly or would it bypass the controller and go into the return passage to tank ?? i dont have the information about this controller or even know who made it, but i can make sleeves to a point but nothing like the original. I dont cobble stuff however if i had a sleeve to go by or a data sheet to go by i might be able to make a sleeve for it if i knew where to find the one that will work. any ideas???
pto pump to a mahindra 3710 backhoe
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rScotty
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Why would a sleeve in an open type hydraulic circuit operate in that fashion? It sounds like a sleeve designed to allow flow when pressurized, and then block any flow from coming back by back pressure.
In an open hydraulic system is that blocking function necessary? The hydraulic pump in an open circuit hydraulic system is pumping constantly at the same rate. Flow rate is always fairly constant and only makes pressure when the stream is diverted by the spool valves to do work - usually in a cylinder. Otherwise the same flow rate just continually returns to the sump. There is no need for a sleeve to block back pressure because there is never any back pressure at the controller at the power beyond port - only at the working ports via the spool valve for that port. There, after the cylinder work is done and the spool valve is manually moved back to it's centered neutral position, its tight fit in the valve body blocks any flow from returning into the contoller.
The result is that all fluid being moved by any pressure in the system simply ends up going "with the flow" to be returned to the sump via the unpressurized return line.
A closed type hydraulic system has a variable displacement hydraulic pump that only pressurizes fluid when there is demand. This type of system is rare in tractors. As far as I know, only JD uses that system in small tractors. Which type hydraulic system do you have?
A closed type hydraulic system also has different elements. It has a pressure storage tank and therefore must have a blocking valve to prevent the fluid stored in the hydraulic pressure storage tank from being forced backwards through the controller.
rScotty
I sent a pic of the sleeve and I did try without it hoping I didn't need it but it seems to be some type of diverter and if removed there is no power just goes straight threw to return with no pressure in controller, so I don't know what type of controller it is but it came off mahindra and is 3710.but the hydraulic controller has a date on it of 2010. Shown in picture that I posted. I think the tractor was around 30hp but that's all I know about tractor it came off of except it has 7.4gpm pump on it and hydrostatic driven. But I know nothing of hoe controller
i didnt post a pic of the spring with the sleeve but i have it to go back in it. I also tried a different spring to see if it would give me a different outcome but no luck there. thinking the original spring might be weak or something.
Well I am really getting frustrated with this controller so I had a friend who helps out from time too time. We took the controller apart first block only and had a peek inside. Well in my opinion there is a lot of difference in this controller compared to my others. This controller only has a small hole around 1/8th inch in it where the fluid travels through to operate the cylinder. And then what isn't being used goes through the valve to return using the sleeve to guide it through a passage to let it go to return. We got talking and it don't make sense to have a 7gpm pump that runs constantly and a controller that I can't seem to adapt to what I need so we put it back together made sure there were no leaks. Tinkered a little more with the how teeth then I decided to try a different controller to see of its gonna work. If it does I'll just buy it and trade the original to someone that has a mahindra to use on there backhoe. So when I get the other controller hooked up we'll see if that works better for my setup. I'll let you know how it goes.
well today i got to put the new controller on the backhoe today and it didn't make much difference other than when i pulled handle fully it did give more pressure but still stalling the tractor so conclusion is that the only thing left is the pump. I am going to figure out a way of testing the gpm so i can see if it really is a 7gpm or is it bigger, have also thought of the amount of flow that could be coming out of it any ideas on how to test this,I think the pump is putting out to much to be 7gpm otherwise it should work????
100 td
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From the start to the finish you have been stalling the motor, overheating the oil, adding coolers and still have poor performance. This possibly means (to me at least), you still have something hooked up incorrectly and/or incorrect valves etc.
Take photos of the entire set up, including all hoses so they can be traced where they come from and where they go to, all valves, close ups of valves with hoses, any stampings or castings of letters/numbers next to hose inlets and outlets, pump and info, relief valve and info, so that the setup can be adequately checked.
Take photos of the entire set up, including all hoses so they can be traced where they come from and where they go to, all valves, close ups of valves with hoses, any stampings or castings of letters/numbers next to hose inlets and outlets, pump and info, relief valve and info, so that the setup can be adequately checked.
Well today I put a wet line kit on my tractor just to see if it still had the problem and it didn't. So the pump was over powering the system. Well I guess I am just going to leave it like it is I need to get the pto pump and tank off of it and clean it up and grease it other than that I guess it's done for now. Thanks for all your help I appreciate it very much
