6420 no hydraulic power to (3)rear 300 series SCV'S

[wore out]

Thanks for the backflow explanation. I wouldn't have expected the LS would go back thru a function that wasn't activated.
Yep, I understand the stud business. The problem is the bottom stud is so long that it hits the 3 point arm when pulling it out. The other two are easy.
I took things apart again. The flat valve next to SCV #2 was gone. When I disassemble and assemble things I always have a large cloth covering the whole area and when done I run a strong roll around magnet 'nut, screw picker upper' around in case I missed anything. I also put vasoline on it to hold it in place when installing. So I don't know where it could have gone.

When I wiped the area where the valve was supposed to be the oil had a 'blackish' color to it like it had some metal particles in it. You don't suppose the valve came apart?

Anyway I put a new flat shuttle valve that I had in and put things back together.
End result- no change-. Next thing is I'll do is pick up 3 short bolts to replace the studs remove #1 & #2 SCV and put only the end plate in.

I can't really check the LS pressure because I have a 300 series SCV in position #3 which requires a 'tap' to be inserted in the line off the R end plate. I don't have the JD parts to do that.

DAMN!

I wonder where the missing disc ended up? Did you ever verify that the Inlet Priority valve is not stuck?

 

[KCinNMO]

DAMN!

I wonder where the missing disc ended up? Did you ever verify that the Inlet Priority valve is not stuck?

I can't figure out the lost disc but I'm going to get a bright light and keep looking, cause it bugs me.

I'm going to keep it simple for now and stay with the basics. Undo what was done to see if SCV #2 is the problem.
Should have started there but I had such a problem removing it to start with I didn't want to take a chance and mess up the threaded studs. But after doing it three times I've worked out a better way to remove the SCV'S. Now I just need to find someplace within 50 miles that has 10mm x 1.0 bolts. Not a lot of options for parts when you live out in the country.

 

[KCinNMO]

DAMN!

Did you ever verify that the Inlet Priority valve is not stuck?

Still don't know were the priority valve is. I posted this Pic before. Is this it?? (circled)

 

[wore out]

Still don't know were the priority valve is. I posted this Pic before. Is this it?? (circled)

Yes.

See Post #32 of this thread.

 

[KCinNMO]

Yes.

See Post #32 of this thread.

I read that but I didn't know for sure if that is the plug to unscrew. I don't want to mess with anything by mistake so I took a picture of the area.

Todays unsuccessful work. Again slid the SCV'S apart. Two flat valves fell out from (what appeared to be)between #1 & #2 ? So I found the missing valve. Put the one valve back in and put things back together. I won't be able to remove a SCV for a while. It seems the 10mm 1.0 bolts are rare things so I'll need to make something that will work.

 

[KCinNMO]

Yes.

See Post #32 of this thread.

I've removed the SCV #2 that I replaced the pin in. I removed it and reinstalled #1 w/o #2.
I have thereby eliminated SCV #2 as a factor. Still no rear hydraulics.

Correct me if I'm wrong, as I understand things the priority valve directs the LS hydraulics to the rock shaft and the SCV'S?? Is so I will check the valve ??? Until I get all the parts I don't know what the LS pressure is.

In reading the "repair manual" it shows how to remove the priority valve (attached) Is this the best way ???
Reason I ask is the "repair manual" said 'in order to remove the SCV'S the rock shaft arm must be removed'. This was incorrect and creates a LOT of extra work in doing so.

 

[M-MAN]

I read that but I didn't know for sure if that is the plug to unscrew. I don't want to mess with anything by mistake so I took a picture of the area.

Todays unsuccessful work. Again slid the SCV'S apart. Two flat valves fell out from (what appeared to be)between #1 & #2 ? So I found the missing valve. Put the one valve back in and put things back together. I won't be able to remove a SCV for a while. It seems the 10mm 1.0 bolts are rare things so I'll need to make something that will work.

Advance auto parts will have the bolts. Others may have.

 

[KCinNMO]

Advance auto parts will have the bolts. Others may have.

Thanks.
I couldn't find any of the particular 1.0 thread taper anywhere.

I wound up cutting up a piece of scrap flat steel and drilling holes in it for the threaded studs.
After removing SCV #2 I wedged a piece of 2 x 4 (the gap was 1 1/2") between the flat steel and the R-end plate. After I tightened it down everything sealed off good. Didn't fix the problem but eliminated the SCV #2 concern.