JD 4430 SCV ?

fordfx413

Member
I have just rebuilt the SCV's on my 4430 tractor.
I installed all new valves, o-rings and back-up
rings. I adjusted each valve with the adjusting
plate. I backed the return valves off 1/8 of a
turn and the pressure valves at a 1/4 turn. The
clearance on the return valve is about .020 and
the pressure is about .060 so the return valves
open first. I installed them back on the tractor
and adjusted the rods. The #1 SCV is behind a
power beyond kit. Here is the problem. As soon as
i flip the coupler lever on the return side, oil
drains out of the coupler on the right side of the
SCV. I let it go for a little while to see if it
would stop and it didn't. The pressure side does
not to this. I moved the control lever back and
forth a little bit to see if it would stop and it
didnt. SCV #2 is fine. I adjusted them both
exactly the same. Anybody know whats going on? Any
input would be great. Also the when running the
draft lever the arms dont start to raise till the
lever gets to about the #4 on the console.
 
A valve is to tight, you were setting them by the book, but a better way is with air pressure. take it back off, set it up in a vice, fit a hose end onto an air fitting, plug it into a coupler, crack the valve handle on slowly (be ready for it to sneeze)making sure the handle is centered, there should be "no" oil/air escaping, adjust that side till a bit of air peeps out and then back it off a half turn, then do the other side, I should have mentioned to loosen up the cam screws a bit on each side first, then snug them when your done.
 
Ok. So adjust one side of the valve at a time? And adjust them so there isn't any air seep by? I don't need to put my adjusting plate back on correct? Air is a good idea, never even thought about doing a bench test before I put it on. Thanks Tim!
 
Sorry I should have made it clear I am speaking of the older SCV under hood on new generation tractors.
 

I am not nearly as talented as Tim S but do use air pressure to test any SCVs I do before sending them home. This important when the valves are carried in and dont have a tractor to test them on. (I am in the process of building a test stand that will use pressure oil from any tractor).
Just a suggestion but did you have a look at the detent roller when you had the cams/rocker assembly out? I have seen it happen that the roller gets a flat on it and messes up "nuetral"
 
Yes it will work on them too, but they are not so easy to repair, as the ones on the rear. You need to have a fitting to screw into the valve since the couplers are not with it.
 

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