John Deere 4020 selective control valve issues

timgc78

Member
Hello I am new to this forum. I have an early JD 4020 with selective controls under the hood. Both valves are in need of adjustment or rebuild. My Fel works but has some quirks when I use it. I just finished repacking all the cylinders to eliminate any problems being caused by bypassing cylinders. I would like to overhaul my scv valves myself anyone out there with experience?
 
A basic re-seal ans adjustment is pretty straightforward, especially with the factory shop manual at hand.

A special "holding tool" and a dial indicator are required. That tool can be "shop-made".

Beyond that, if the valve seats need to be repaired you need several special tools.
 
I have the tech manual and dial indicator. I can also make or buy the adjustment plate. Does anyone have any specific do's or don't's when reassembling and adjusting the valves? Troubleshooting ideas would be nice also.
 

We have technical wizzard on this site with a test and calibration Bench. Seen the rig myself and it's done right. The rebuilt valves leave his shop better than new for a modest fee.
 
my neighbor went thru this on his 4020. loader would do all kinds of crazy moves, up down by itself, random bucket cycles. guy from the local john deere dealer looked at it, and said the valves were pretty well wore out, be spendy to put em back and they are kind f tricky to get just ight. what they ending up doing is mounting a separate spool vale for the du-all loader, then tapped with a tee of the hydraulic output on the right side of the tractor below the brake pedals. deere has a trans oil filter cover that is drilled and tapped for a hydraulic return, or you can drill and tap your old cover. set the spool valve for a closed center system and you are good to go. both his 4020's are set up this way.
 
You know I had considered putting a valve on the loader and not using the scv's. By the time I get a valve, hoses, fittings and fabricate a bracket to mount the valve I could pay a good tech to repair my valves. Anybody out there have extra scv's for sale working or not. I need one to tinker with.
 

I skimmed through your post and it didn't click that you are using a front end loader with dash hydraulic valves.
I would have been all over that saying forget about the dash valves and use a aftermarket joystick with the previously stated direct connections.
Afterwards you will wonder why anyone would try to operate a loader though a SCV instead of a direct plumbed joystick.
timS on the JD section of this site is the hydraulic rebuild genius. Power steering, front pumps and SCV's like new.
 
It's does seem as if it would work faster w a valve for the loader considering it would be tapped in right after the priority valve. If my thinking is correct it should have the main pumps 16 or so gpm vs going through the scv's and have 6 gpm. I intend to restore my 4020 and I want it as mechanically sound all the way around before I even consider body work or paint. Scv's still need refreshing. If they were fixed I believe I would be happy with how the loader operates w the scv's.
 
Guess I'm just a simple guy. Been using my 4020
(67 model) with GB loader with the hoses out the
scv's and a three spool valve (use a bale clamp on
it occasionally) for about 25 years without any
real problems and the loader is plenty fast enough
for me. Rarely use the scv's for anything else
but if I need to I just unplug the loader hoses.
 

I'm not sure how you could say that being that you have not operated the same tractor and loader with a joystick and proper hydraulic connection?
 
wengers of meyerstown has rebuilt scv valves for $775.00, might be a better way to go, then you could open your old one up and see if its worth repairing.
 
Yes they do. Several ag suppliers have exchange scv's in the $700 range. I believe I have been convinced to put a valve on my loader. Now here's my next question. I've learned recently that there are several valves that will work with the fel. Which brand/style two spool valve is gonna work best for my loader?
 
surplus center has quite a selection of valves. you could also try shoups and agri-supply. most can be converted to open or closed center. be sure to get one that has a "float" function on one of the valves. its real handy for back blade-ing and grading. altho the joy stick valves are cute and fun to use, i prefer the two handle spool valve. simple, no cables to diddle with or break, or to keep in adjustment. joysticks are on the spendy side too, as most of us have limited budgets.
 
just looked at surplus centers web site. they have a 25 gpm dual spool with float that is convertible for closed center for 217.95, the part number is 9-6702-f. has 3/4 inch inlet and out let and 1/2 inch working hoses. that should be about the right one. on my neighbors 4020, his spool valve is mounted on the verticle rear mast of the loader, i made him a bolt on shelf. that way if he takes the loader off, the valve stays with the loader. or you can mount it on the fender.
 
I have been on surplus centers website. Gonna buy the Prince joystick valve and weld up a nice bracket from the axle up to the valve instead of using the mast as a mount. I really wish I could find an original Deere valve bracket that was on a loader with a valve!!! If anyone happens to have one out there I'd be a buyer fora reasonable price! Thanks to everyone for the advice!
 
You can get a joystick with cable for the prince that is pretty reasonable, do not need big mounting in the way then.
 
You can do it - I just did one of mine a couple of months ago. I
can't recall what it ran me but it wasn't bad. It is literally about
six little round seals and one big o ring style for the cover. It
will take you longer to pull off the seat-side toolbox to unbolt
the thing. A few bolts and you will have it on the bench. It lost a
little fluid when I unbolted it but not enough to even top it off. It
looses more from leaky loader cylinders. I think it took me a
couple hours from start to finish. All I had to help me was the
parts break down picture I had Deere print out.

I have run the loader with one of the units locked on live for a
lot of years. I have been meaning to plumb it in but other
things come up. I have three loader tractors so it isn't the end
of the world if it is a little slow. It does get lots of use, though.
 

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Back
Top