very basic:
Hydraulics 1�1 for Beginners | Agriculture | Tractor Supply Co.
hydraulicsupermarket.com (I'm not a huge fan due to an experience with them at a previous job, but they do have a lot of good information)
open vs. closed relates to control valves. (which are spool valves, but technically lots of different kinds of valves use spools)
open center: oil flows from pump to reservoir (aka tank) when the control valve is in neutral (no work request by operator). Shifting the control valve blocks this path and diverts the oil to a work port. If you need to operate more than one function at a time it is difficult to precisely split the flow, and the function with the highest pressure requirement determines the system pressure.
closed center: oil does not flow thru the control valve when it is neutral. Shifting the control valve connects to pump port to the work port. Can only be used if there is a way to unload the pump - variable displacement pump, flow diverting "unloader" valve between the pump and control valve, etc. More complex and expensive, but you save fuel because the pump only flows what is needed and close to zero when there is no demand.
power beyond allows you to hook up another control valve downstream of the existing control valve, while leaving the first valve to operate normally.
- Plain control valves have two main passageways, one connected to the pump and the other to the tank. If you try to add a 2nd control valve after the 1st you will have major issues trying to operate a function on both valves at the same time. (lack of flow to 2nd valve, excessive back pressure on the 1st resulting in lost power)
- Control valves with power beyond (aka High Pressure Carry Over) provisions have three main passageways. If the power beyond provision is not utilized the power beyond and tank passages are tied together and it operates just like the valve above. But if you isolate the power beyond and tank passages (usually by adding a plug or sleeve) the unused oil in the pump passage gets passed to the 2nd valve. Both vales need their own tank line.
And for any valve configuration above a given section (one spool or set of outputs) can have additional features like 4 position w/float, detents, etc. And unless you are dealing with a high end control valve with flow sharing the upstream function gets priority. This may affect in what order you connect your implement functions.
Most tractors use a standard 1/2" (nominal ID) remote coupling you can get at MANY different places, with numerous different kinds of threads to match what you have. Some will have balls inside the female coupling and some will have a cone but they can usually be interchanged as long as they meed the ISO 5675 standard (aka Pioneer coupling). Generally cost is related to durability and ability to connect with some pressure in the line. One "remote" has two female couplings on the tractor with the male couplings on the implement. Rarely you may see where someone has reconfigured a tractor to have one male and one female per remote the eliminate connecting an implement incorrectly, especially a FEL. I just put a zip tie on the left or top hose.
The cat's meow are these lever style female couplings from Parker that can be connected under pressure that came standard on Steiger tractors for years, but they are overkill for most applications.
Lever Operated, Tractor Quick Couplings, Connect Under Pressure, Breakaway Sleeve, ISO 5675 - Pioneer 92�� Series Couplers | Parker NA
If you want to use something with a hydraulic motor you may need a case drain - essentially a connection directly back to tank to keep backpressure at a minimum, but it also bypasses the filter.
I'm pretty sure your Mahindra is open center. What you need depends on what you already have and what you want to do. Lots of people on this site will chime in if you lay out your specifics.
ISZ
