John Deere 650 (1983) - Hydraulic Stop Valve is seized

[Tuckersm]

Since I bought the tractor, my 1983 John Deere 650 has issues with the hydraulic stop valve. I have tried everything, but I can not get it to turn in either direction. There is some rust on the visible threads. From the best I can tell, it is in the fully open position. When I try to lift any attachments, it's quite fast and choppy.

Has anyone else had this issue of the valve being seized? And if so, any remedies to free it up? I'm out of ideas.

 

[KWentling]

I believe the stop valve only affects the lowering function. Not a JD owner.

 

[Jims1025R]

I bought a 650 used in 1989, that valve was seized. I had the tractor until last year (lost in a fire), and never managed to free it up, despite efforts with penetrating oil, and heat. I finally broke it off trying to hard, and that was that.

The speed of lowering the rockshaft is controlled by a smaller valve with a roll pin as a "lever" for your fingers. If I recall, it's on the right side, under the seat.

 

[TractorTech]

The valve controls only 3PT hitch drop speed or it can be closed to hold the 3PT.

The valve is similar to a faucet valve in that it has a stem shaft in a gland nut sealed by orings. With the tractor off and the hitch all the way down, you can unscrew the gland nut and take the assembly out to better work on it to free it up.

 

[California]

That JD 650 was built by Yanmar and shares that part with YM2000/YM240 etc from similar years, early 80's. TractorTech's instructions are great for disassembling that valve.

The valve is only to lock the 3-point in the 'up' position for safely working under an implement. If you don't need to do that then the valve is irrelevant.

There is a separate drop-rate valve as Jims described above, a tiny T-handle on the side of the transmission.

The Yanmar (classic) forum here has posters with lots of related experience.

 

[Tuckersm]

I bought a 650 used in 1989, that valve was seized. I had the tractor until last year (lost in a fire), and never managed to free it up, despite efforts with penetrating oil, and heat. I finally broke it off trying to hard, and that was that.

The speed of lowering the rockshaft is controlled by a smaller valve with a roll pin as a "lever" for your fingers. If I recall, it's on the right side, under the seat.

Yes, the little lever is under the seat on my 1983 as well. I'm giving up on trying to get the other piece free before I also break mine. Thanks for the feedback.

 

[Tuckersm]

The valve controls only 3PT hitch drop speed or it can be closed to hold the 3PT.
View attachment 762777The valve is similar to a faucet valve in that it has a stem shaft in a gland nut sealed by orings. With the tractor off and the hitch all the way down, you can unscrew the gland nut and take the assembly out to better work on it to free it up.

I ended up doing what you suggested. Despite lots of penetrating oil, some heat, and letting it soak in Evaporust for a solid 12 hours, it just won't free up for anything. I'm just going to leave it before I end up breaking it. Thanks for the feedback.

 

[Tuckersm]

That JD 650 was built by Yanmar and shares that part with YM2000/YM240 etc from similar years, early 80's. TractorTech's instructions are great for disassembling that valve.

The valve is only to lock the 3-point in the 'up' position for safely working under an implement. If you don't need to do that then the valve is irrelevant.

There is a separate drop-rate valve as Jims described above, a tiny T-handle on the side of the transmission.

The Yanmar (classic) forum here has posters with lots of related experience.

Luckily I don't have any need to lock it up at this point. I did what TractorTech suggested to make it easier to work on. However, I just can't get it to free up despite copious amounts of penetrating oil, heat, and a 12-hour soak in Evaporust. The holding power of rust is quite impressive in this case. At this point, should I ever find myself need it to function, I'll have to pony up and buy a replacement one. Thanks for the feedback.

 

[California]

If you do need parts - Hoyetractor stocks a broad range of parts for Yanmar including the Yanmar-built Deeres - 650, 850 etc.

 

[Tuckersm]

If you do need parts - Hoyetractor stocks a broad range of parts for Yanmar including the Yanmar-built Deeres - 650, 850 etc.

Thanks. I'll keep that in mind. Finding parts for these older tractors can be a real bear sometimes.

I put everything back together this morning and everything is doing what it needs to.