I doubt it is a precursor to any failure. Just for general info, here is how that system operates and what to look for:
When you move the 3pt lever to raise those 3pt arms, you are manually opening the 3pt lifting valve to let hydraulic fluid into a cylinder (usually located in the casting under the seat) where the fluid pushes down a cylinder and raises the arms
.
After the arms raise up to however far you have moved the 3pt lever, the 3pt lifting valve closes. That traps the hydraulic fluid in that cylinder and the arms stay up.
When you move the 3pt lever to lower the arms, you are manually opening that 3pt lifting valve, thereby releasing the fluid from the cylinder so it can return to the common sump.
On it's way to the sump, the fluid is restricted by an an adjustable needle valve - that is the hand adjustable "speed knob" beneath the seat. The speed knob is just controlling the size of an ajustable orifice. So it is nothing more than an adjustable narrowing in the fluid pathway to the sump and it's easy to see how narrowing the exit would change the lowering speed. In fact, if the valve is closed completely the fluid is blocked and the arms won't drop at all. That's not a mistake, it's useful for some implements and for some maintenance to be able to hold the arms up.
However, I don't see how that exercising that needle valve could change anything at all. About the only thing that might have happened mechanically is that there might be some oil-borne crud that got caught in the narrow valve pathway and blocked the flow......which then was dislodged by moving the valve. But there shouldn't be much crud in that oil. An what there is should be in the micron side. Certainly not that large enough to block a needle valve.
For most tractors, decades can go by without adjusting that valve. You gain nothing by periodically exercising it that I can see. I'd say that chances are better that someone was just messing with the tractor and turned it to the full lock positon accidently. Maybe they thought it controlled some seating function. It's in the right place.... That's easier for me to envision than crud clogging up the valve itself.
One other possible mechanical scene is worth mentioning. It sometimes happens that there is some water - usually condensation - that gets into the hydraulic fluid. With water in the fluid, if the 3pt lift arms are left in the same position for months then the 3pt lift piston or piston seal will often adhere to the 3pt lift cylinder wall. It will generally break loose by jumping on the arms, but indicates that it is time to change the hydraulic fluid.
Hydraulic oil that has lots of water in it will become milky instead of clear. That means it is way past time to have changed that oil.
rScotty
Merry Christmas everyone and enjoy the recliner today!
