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[rScotty]

I doubt any extra passages on this valve for pilot oil since it is mechanically operated and also doubtful the gear lube would cause failure with increased temps. If anything the increased temps would allow oil to flow easier.

Is this valve multiple sections held together via tie rods or bolts? If these were took apart was it assembled in a manner that is causing mechanical binding as it heats up such as tie rods tightened to tight? This can and will cause spools to bind.

Yes, I didn't think of that. Maybe it is a sectional type. If so, it could be disassembled, cleaned, and tested. I've never seen one like you descibe used as a 2 spool loader valve - but that means little.

I have seen those multiple section valves held together that way in backhoes and rear remote stacks, just not in loader valves. In fact, taking mine apart is on the "to do" list.

I'm taking a break from shop work. I'll search for it.

LATER.... I can't find a single example of a multiple section 2 spool loader control valve. All I find are standard monobloc body type. That doesn't help.
Have you got a link?
Maybe the Europeans make one or maybe Mahindra found a stash we don't know about.

Keep the ideas coming - at worst the OP can gamble and replace that joystick for 2/3 hundred bucks and an hour's work. Sure beats the other problems he might have had with PS and shuttle.

rScotty

 

[oldnslo]

If accessible disconnect the push pull cables from the spools. That would then separate the joy stick from the valve spools. He could then manually move the spools and joy stick to see where binding is.

I have also not seen a standard loader valve that isn’t a mono-block design but did Mahindra mount this valve to a casting like some rear remotes?

Pictures of valve would certainly answer some of these questions.

 

[oldnslo]

Parts breakdown certainly looks like a mono-block assembly.

Did this problem start before the valve was taken apart or after? Since problem gets worse when warm I am leaning towards something expanding and binding which would point towards the valve but what changed to cause this?

 

[oldnslo]

How difficult is it to access where the joy stick cables connect to the valve? If not to difficult could you disconnect the cables when unit is heated up and binding to isolate valve problem or cable problem?

Cables can corrode and bind just trying to imagine a scenario where heat would make them bind worse and why after 50 hr service.

Valve binding after 50 hr service doesn’t make any sense either.

 

[oldnslo]

Air would make the loader spongy but should have no effect on how the joystick moves.

 

[Rich B1]

If you had the valve off and apart, is it possible you overtightened the mounting bolts when the valve was reinstalled?

It is also possible the valve was shimmed to avoid being put in a bind when mounted if the mounting plate is less than flat. Loosen the mounting bolts a it and see if the valve gets a gap under one or 2. If so, you may need to shim it to avoid binding the spools when the bolts are tight.

 

[rScotty]

Its not to bad to access, the cables looked fine when we took the valve off an cleaned it, it may have been doing from the word go, i got the tractor in Jan. of 2020 an only used it to put in hay for the cows, moving wood for the heater, not much run time all at one time. The dealership said it was air in the system.

OK. So what I'm hearing is that maybe the joystick being stuck has nothing to do with the wrong oil at the 50 hour service. Maybe it was always that way and you are just noticing it now that your running the tractor on longer jobs - long enough that the tractor has a chance to get warm...or hot.
And the joystick works normally when cold or for the first half hour.
And the joystick has been getting sticky now long enough for you to get it flushed twice and someone to take the joystick apart and check the O rings.
And the dealership said it was air in the system.

All that about right?

BTW, I doubt air could cause a problem in the Joystick. It might cause the whole hydraulic system to overheat, though.

That type of hydraulic system is common to almost every compact or utility sizetractor made. All of them will normally self-purge of air in 5 minutes or so. The only way long term air in the system could get there is if there is a loose connection or bad hose allowing air to enter the the suction side of the system as the tractor is running. Air leaking into the hydraulic system can only happen in the suction portion which is the lines between the transmission sump, the hydraulic filter, and the line up to the hydraulic pump.
Air leaking into a hydraulic flow is pretty easy to find and cure. if you have a leak it willl not show any symptoms to tell you where the air is getting in until you turn the motor off. Then there will be a minor drip that wets the outside of the hoses. Typically it can be as subtle as a few spoonfuls of oil under the tractor after it sits all night. Or a hose that is wet on the outside of the hose.

An air leak in the suction side of the system will make the controls feel spongy and makes the cylinders work differently at the end of their stroke than at the middle. Also asuction airleak is instantly obvious to the experienced mechanic because the return hydraulic oil in the sump has so many microbubbles that it is no longer clear. It looks murky - but then it clears up and becomes clear oil again after sitting overnight.

Is any of this sounding famiiar?

rScotty

 

[Rich B1]

Thank you Sir, The problem was before the valve was taken off an cleaned.

The mounting plate may have been less than flat from new if that is the case. It is worth a check.

 

[rScotty]

Can not say that I've noticed anything under the tractor. there again not really looked. I'll look the tractor over good an check fittings an hoses an put down some cardboard after i have run it. i thing the bubble thing you spoke of may be the problem I'll run some in a clear jar an see. Yes i think you are on to something here it does get hot.

The other thing that will make hydraulics hotter than they should be is if there is a restriction in the pressure line. Anytime oil has to be forced through a small orfice it gets hot fast. You can heat up your whole hydraulic oil supply in a minute or two by holding the steering against the stop until it begins to whine.
In fact, JD recommends doing that on their big 310 backhoes if the oil is too cold to flow on a winter day. ...

And of course the other thing is that there may be an obstruction somewhere doing exactly that. Something could have clogged or broken loose internally and be jamming up the flow. It happens. If so, a pressure gauge will find it pretty quickly.

If nothing else works, and the problem really is just the fluid getting too hot, you can always add a radiator. It beats fixing a tractor.

rScotty