Yanmar 1500d 3pt sticking in the up position

[al b]

The arms go up when I start it and rev it up around 1500rpms and won't go down until I slow it or turn it off, foes down really slow, doesn't matter where the control lever is. How many gallons of hydraulic do I need to do a change?

 

[clemsonfor]

To me sounds like the valve under the seat is stuck open, which as rpms increase increasing fluid volume it raises the hitch and as they drop pressure falls and so do arms, it sounds like the valve is stuck open regardless to handle position or trash in the valve or maybe orings that are leaking bad internal to the 3pt valve under that pressure line under the seat.

 

[al b]

Just got back from Tractor Supply, got 5 gal of hyd/trans oil. I'm going to look for the strainer and replace the fluid. See if that helps.

 

[clemsonfor]

i really dont think that is your problem, but probably wont hurt either. While your hands are dirty take that valve off its only 4 bolts and then the big pressure line on top, look to see if there is trash in it or anything that looks wrong, wash it with deisel and then blow dry then replace.

 

[al b]

I took the valve off and cleaned it, seemed to be good on the bench, but once I put in on and started the tractor it would get stuck again. Did that three times. The last time I cranked it with the banjo fitting in a clear bottle until the new fluid came out, put it back together and cycled it a dozen times, the little button on the valve moved in and out without getting stuck which is an improvement. But the deck still won't come up like it would before, almost as if the big spring on top got weaker, I had to put some pressure on the button to make the deck go up. I took the screen out and cleaned it, it was really dirty.

 

[al b]

I took the valve off and cleaned it, seemed to be good on the bench, but once I put in on and started the tractor it would get stuck again. Did that three times. The last time I cranked it with the banjo fitting in a clear bottle until the new fluid came out, put it back together and cycled it a dozen times, the little button on the valve moved in and out without getting stuck which is an improvement. But the deck still won't come up like it would before, almost as if the big spring on top got weaker, I had to put some pressure on the button to make the deck go up. I took the screen out and cleaned it, it was really dirty.

 

[deepNdirt]

most likely the O-ring on the small piston in the valve, done this very same thing with me few months back, took it apart freed up the piston put it all back together worked for 3 lifts and then got stuck again, the next time I disassembled/removed the piston from the valve and found the O-ring had a nick in it,.... replaced the O-ring and has never got stuck again,
Note: I clean and air off all parts and pre-lubricated with hydro oil as I was putting it back together,:thumbsup:

 

[al b]

A parts diagram from Hoye Tractor shows two more parts inside the plunger then I have on mine. #26 and #16 or 23. I'll see if I can post the diagram.Yanmar Tractor Parts: 3_POINT_CONTROL
I have a ball, then a spring, piston with a o ring on it, that's it.

 

[al b]

I'm back at it today and took a few pictures. The screen was dirty with small metal chips and it got cleaned, and those are all the parts in the plunger. I know the last picture is hard to see but there is a grove where a cir clip could fit. I'm going to the hardware store to see if I can find one.

 

[winston1]

Here is the circlip. Yanmar Tractor Parts: CIRCLIP - 1/2 CLIP - 2 REQUIRED