Ask the Mechanic
Lower the Hitch
READER: I have a John Deere 4230 tractor that is leaking around the load-sensing shaft seals. I removed the load shaft and old seals, and found a little wear on the shaft. I bought a new shaft and seals, but when I try to install the shaft, about halfway into the tractor, it hits something. I don't want to force it in, but I don't know what to do to get the shaft to go all the way to the other side of the tractor. Can you give me any clue as to what is in the way of the shaft?
STEVE: The load-sensing shaft on your tractor is totally mechanical. The shaft is designed to flex and activate the 3-point hitch in order to help keep a ground-engaging piece of equipment at a constant depth as soil and terrain change. The shaft stays in close contact with the actuator arm that raises and lowers the 3-point tool. Sometimes, the arm rests in the path of the load shaft when inserting. The first thing you need to do is make sure the 3-point hitch is all the way down. If the shaft still hits on the way in, you will need to remove the plug with a 1/2-inch extension. You will see a castle nut inside the housing. Take a long punch or screwdriver, and push in on the castle nut, and now you are able to insert the load-sensing shaft without a problem. The John Deere 20, 30 and 40 series tractors are all alike with the draft control repair.
By the way, these tractors are hard on load-sensing shaft seals. One way that I have found to extend the life of the seals is to tie the lift arms together when they are not hooked to a 3-point implement. They slam back and forth when free, and this action works on the seals. A small chain through the balls on the drag links, a rubber strap with hooks, a piece of old rope and even baler twine will secure the drag links.
> Write Steve Thompson at Ask The Mechanic, 2204 Lakeshore Dr., Suite 415, Birmingham, AL 35209, or email firstname.lastname@example.org.
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