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Clooney
12-03-2002 05:43:32
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Re: 730D Power steering trouble in reply to Brent Fetters, 12-02-2002 21:43:33
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Brent, it might be as easy as turning up the flow control in a little to allow more oil to flow to the control valve. [try turning the flow control valve in a little at a time to see if that helps]
~If the flow control adjustment doesn't help [I presume you have already tried sliding the steering valve to the rear a little] you could have anything from worn actuating sleeve helix pins or parts, to wear or loose parts in the steering valve, to a worm cam, to a weak or misadjusted cam spring, to worn worm bearings, to actuating sleeve [helix] end play not set correctly, to low pump pressure, to internal leakage at the P/S vanes, or worn vane surfaces on the quill surfaces to ? or some of the above combined.
~I don't know what you have already done, but I would suggest you try to find a 0-2000 lb pressure gage & make an adapter to install the valve in the pressure tap port on the steering valve then measure the turning pressure with a hot system. If not even [or is lower on one side] when turning in both directions either adjust the steering valve position or check for worn cam, too tight a cam spring, tight helix, worm helix pins & or worn operating sleeve slots, or? ~The next thing to try is pulling the forward pressure line from the steering valve to quill & see how much oil is by-passing the vanes when the wheel is held all the way to the right at high idle hot [should be less that 1 qt in 30 seconds]. If you have excess leakage there replace the vane seals & "O" rings & look for scoring on the quill surfaces.
~You problem isn't unique but I have found isn't always the same things. To repair it completely & correctly the steering gear should come off & ALL operating parts checked for wear, proper adjustment & nothing being loose.
~If you don't want to tear it apart at this time you can try a few things to cover the problem; try turning the flow control up as far as you can without wheel flutter,,,try using a pressure gage to center the steering valve [with the front wheels on a high traction surface like concrete] slide the steering valve forward or rearward until you obtain the same initial pressure spike for both L & R turning,,,try removing gaskets from between the steering gear & bolster until you get the least backlash [without any binding],,,try backing the worm shaft cam tension spring nut off a few notches to allow easier cam displacement,,,try moving the actuating sleeve adjusting bushing in & then out 1 flat to see if that will help,,,if you live in a warm climate try 20W50 oil in the steering system [15W40 in cold climate].
~I have worked on quite a few of the old [in your case later design] Deere power steering systems over the years & while helix pin & slot wear, or worm shaft cam wear, or spring adjustment, are a big factor in non linear steering, it could be almost anything, or in most cases a stack-up of many smaller things that add together to cause a steering problem.
~What I usually find are internal problems that can be due to long term wear or abuse, but as long as the pump pressure stays high & the fluid flow stays high & all the steering parts turn freely it doesn't show up as a problem. As soon as the pump pressure gets a little low, or the flow slows down a little, or the front tires get on a high traction surface, any internal problems become apparent as the steering gear hangs at the problem rather than turning quickly through the problem.
~I guess I haven't told you how to repair the problem but have given you things to look at. It is easier to answer your specific questions than try to guess at what it is & lead you in the wrong direction. The best way to repair those old Deere steering systems is to look at all the parts, then get a steering manual, then figure out EXACTLY how it operates, what does what & when, so you thoroughly understand how it operates & why. [it is really a simple system that looks complex]..
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