My JD 730 was leaking power steering oil out of the bottom bad. Probably the bottom "O" ring. None of the backer rings were left and the "O" rings had flat spots worn in them. Bought the service manual, tore it apart and cleaned it up the last couple of days. Pretty much everything checks out OK. The one place I can see some wear is in the bottom casting which I believe is called the quill. Over the years the outer race of the thrust bearing (carries the load of the tractor when operating with a narrow front) has slightly worn into the casting. I don't think it was machined that way. Seems like there is a groove of maybe .020 where the outer race would put pressure pushing upward against it. This wear would cause the spindle to move upward slightly. Moving the spindle upward would cause the bolted rotating sealing vane to slightly move upward in the "cylinder" of the power steering system. Is there enough "give and take" (clearance) in the power steering cylinder to allow for.020 - .030 upward movement of the rotating sealing vane without causing premature wear to the seals? Am I over thinking this small amount of wear and slight upward movement of the spindle or should I add a thin thrust washer under the inner race of the thrust bearing moving the spindle downward some? Another thing is the narrow front is coming off and a square wide front is going on. That takes almost all of the stress off of the thrust bearing and quill and with enough end clearance on the spindle the sealing vanes could center themselves in the cylinder. Any ideas appreicated.
Re: John Deere 730 power steering repair in reply to Andy R, 06-13-2020 20:11:23
The place to add or remove shim is under the worm gear at the top of the pedestal. Measure end play and adjust as needed to a range of 0.004 - 0.021. I have seen some with no and one with as many as four when replacing seals in some of my own.
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