John Deere 850 after S# 009001, SCV valve

[vt woodchuck]

Tractor S# CH 0850 S023370, has p/s, backhoe, front end loader with float.

You guys helped me put p/s on this tractor in 2020, I hope you folks can help me with the SCV valve.

The SCV on my tractor is made by Dukes Fluid Power, #1627 AN, JD original part #RE 19910, revised # AM 107083. With Power beyond (PB)
This valve was used on 850, 950, 1050. Dukes sold to Sauer, who sold to Danfoss, then sold to QCC. I have been searching for some time for a replacement, new or used, QCC sent one to me, but the "in" and "out" ports were 1/4" instead of 1/2", also the ends on the spool valve were different, and the PB was Different. They said that was the best they could do, as the part was obsolete. They were very helpful, and graciously took it back.

I have located a (nos) Dukes 1627 FY, does anyone know the difference between 1627 AN, and 1627 FY.
The differences I see:
#1- On mine, there is additional casting material near the outlet port. Could it be a bypass passage for the float position?
#2 - On mine, on the spool end, there are 2 cast bosses with a hole drolled thru, next to ports "A" and "C", these holes are not used in my application.
#3 - On mine, there is additional casting material under the data plate. The data plate on the new valve is on the other side.

Thanks for your time, and any help would be greatly appreciated, also any salvage yards I can call.
Thanks, Mike

 

[rScotty]

Hello, I'm curious why not just buy your tractor a brand new aftermarket loader control valve?
It seems like that would be far better than a scrapyard valve.
Do you just want to keep it original JD parts?
BTW, what happened to the old control valve that makes you want to change it?

You can buy replacement control valves which will bolt right up and have the features that you want.
Most will be less expensive than original JD parts - even if you do find JDs - and you can select the quality you want. Most will be in the $200/400 dollar range.

You want to specify,
two spools - or as many as you have circuits to control. Get 3 spools and control a grapple.
flow rate - you want 11 to 20 GPM - check your specs & get the smallest one.
Pressure rating....the JD850 psi was fairly low, but check that the valve is over 2000 psi.
You want Open Center type, and be sure to order the optional Power Beyond (PB) sleeve.
You do NOT need or want the optional Closed Center sleeve for the PB out port.
I like the style that has the pressure relief valve built into the Control Valve body. use 2030 psi +- 150.
To match yours, get a valve that has a float with a detent on one of the spools.

Port threads - you might as well match your existing hoses.
From the looks of our photos, your old loader control one use SAE O-Ring Threads.
The measurements you took for thread type & size don't seem right. Best check them again.
I'd guess your IN & OUT use #10 SAE O-Ring (7/8x14 parallel thread)
And the cylinder work ports probably #8 which is 3/4x16.
All SAE O-Ring is parallel thread. NOT plumbing pipe tapered threads.

BTW, If you find the Control valve you want and the port threads are not right, you can always use hydraulic thread adapters. Adapters add a little bulk, but not much, and sometimes have handy features like swivels. They aren't expensive, and are made to adapt between most every hydraulic thread and fitting that exists.
luck,
rScotty

 

[vt woodchuck]

Hi Scotty,
Thanks for your reply. My old valve was unusable due to internal rust in the check valve housing opposite the end with the exposed spools. the springs and check balls are badly pitted. I have not been able to locate how water is getting into the system. All the shifter boots and seals appear to be in good condition.
The only new valve I could find was from QCC. This valve is obsolete and NLA. They tried to match it with what they had.
Please read my original post again.
The purpose of the post was to find out the difference between the AN and the FY before I committed to buying the 1627 FY, because there are some physical and visual differences.
Fortunately for me the owner of the NOS. valve was willing to let try it, and return it if it didn't work.
Long story short, it did work, and it does have the float detent.
Thanks for your reply and input.
Mike