I have a John Deere 4020 diesel that has developed an annoying habit of swerving to the right when driving. If you are fast and turn left it straightens up but is obviously dangerous on the road. When I start it up and it’s stationary it veers to the right on its own. Any idea what is causing it? I am thinking that a seal or ring has failed somewhere, but have I heard that it is a difficult job restoring the steering valve block? I am new to this site so hello and hope you can help me.
The valve shouldn’t be difficult to rebuild for someone who is moderately mechanically inclined. I would suggest asking for the service manual before you start.
I guess you’ve never seen the guts of a JD steering valve. When I was a service manager for a JD dealership, I had several mechanics who were unable to adjust the valves correctly the first time and had to redo the valve adjustments. The 4 valves inside require a special setting plate, plus a dial indicator to get the correct clearances. Also, I think the problem is leaking o-rings on the steering motor which can be replaced by removing frt shaft and a side frame.
I have a similar steering problem. I was told to unhook the hose from the front steering section at the top of the hydraulic cooler tower and to plug the nozzle quickly as it would leak at the top of the tower. Then put the hose in the can and let it drain. Then start the tractor and turn the wheel to the right and see how much oil comes out. Turn left and see how much oil comes out. If it is just a few drops, the front steering section is fine, if there is a jet the front section is not fine. You should have a helper to do this.
I have explained my steering to some mgr’s of service, that is, the wheel lock, does not turn, when turning to the right, the wheels that follow the steering turn some time later by as much as a few to 5-10 seconds (kind of a guess). This happens at startup after sitting even one day. I changed the hydraulic fluid, the filter, and the transmission screen was clean. This is a 69 3020.
I was also told that the steering valve bleed is also done as long as the steering is on full left and right and there is no need to do manual steering valve bleed.
3 service technicians have said it is the steering valve block under the hood. Please comment on this if you are so kind. Thanks
I did the leak test on the hydraulic cooling tower by unhooking the hose from the front steering motor and putting it in a can and then started the tractor, 69 3020, turning the wheels first to the right and then to the left and got only a few drops of oil with each steering turn.
I’m listening and reading which is the front motor or the steering valve, I just would like to know which one is for sure if possible before breaking things apart.
Hope TX Jim gets some more on this , I am a little concerned about driving in the ditch at some point if everything goes south all of a sudden, it works fine after it runs for a minute or two.