JD 730D Power Steering

PV · Aug 2, 2015

The steering works well but can lock up occasionally when turning out of a sharp turn. I can turn tightly one way, but then it may jam up when turning back. Most times I can quickly force it free, as if something is catching, but the other day it proved to be more difficult. I'm sure I have to take the steering assembly apart but it
would be nice to know what could be causing this.
Any suggestions welcome.
Thanks
Peter

matthies · Aug 2, 2015

I just finished a 50 with binding issues like you mentioned. Had to add a couple thicker shims between the pedestal and the valve assembly. I would jack up the tractor and steer it manually to see if it still binds, then add shims and retry. chris

fixerupper · Aug 3, 2015

When it locks, does if free up if you turn it back a twitch and then try steering in the direction you want to go? If things are a little worn in the steering valve it can lock when returning the wheel back to straight after a turn. The two bangers have a habit of doing that. It's the most common cause of locking. More than one has gone in the ditch after turning a corner on the road and the wheel locks while trying to straighten out after turning. Years ago a neighbor's 730 was ditched because of it. Tractor did not roll over thankfully. My 630 went in the ditch because of this when a young man was driving it. By the grace of god the tractor did not roll over.

Kent Petersen · Aug 3, 2015

there are 2 dowel pins in the operating sleeve that can clause this they need replaced

PV · Oct 13, 2015

Which gaskets are you referring to - the ones between the worm housing and the pedestal, or the ones between the worm housing and the valve assembly?
I'm wondering if the worm and gear are jamming up because of too much clearance. I have quite a bit of backlash, but it's all cumulative wear through the system and difficult to isolate.

PV · Oct 13, 2015

Thanks Kent. Someone told me it could be a loose vane bolt in the steering cylinder. But that all checked out OK. I replaced the vane seals anyway.
The problem indeed seems to be with the valve assembly so I replaced the two pins and dressed the cam faces as best I could.
The problem is still there but in a different position with jamming now occurring closer to straight-ahead. Yes, there is wear in the helixes, but doesn't seem enough to cause jamming.
I'm coming to think the problem could be related to the worm/gear mesh. Their positions would have changed with reassembly and I had to dress some small burrs on the teeth edges of both. With wear, maybe there's now not enough engagement. I do have quite a bit of backlash. I'll be checking this next.

PV · Oct 18, 2015

Got the steering working, finally. Replacing the two dowel pins somehow changed the worm/gear mesh and jammed things up worse. I dressed up the cams and adjusted the worm end play reducing it from 10 thou to about 1 thou. The existing gasket between the worm housing and the pedestal was 20 thou. I started off by reducing this to get a reduced backlash using only a 5 thou gasket. It immediately jammed up solid. I then added another 30 thou to the original gasket and the steering worked well for about 20 min when it got hot enough to jam. I then added another 50 thou gasket (total of 0.1 in thickness) and it now seems OK. Ran the tractor till it got over 140 deg and seems fine. The backlash is no where near what the manual recommends but I'll take what I can get.
Thanks everyone for help and suggestions.
Peter

JD 730D Power Steering

PV

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matthies

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fixerupper

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Kent Petersen

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PV

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PV

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PV

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