Kubota M6800 steering

Catskill Pete · Dec 10, 2009

Thought I would try a tractor question on here.
I am working on a Kubota M series and the power steering quit on it. I have worked on other color machines but this M6800 is a little different animal, I guess Kubota does things their own way. It has hydrostatic steering with its own pump. Steers ok but no power steering. Pump seems to be working based on cracking the line and eyeballing it. I"m still trying to fabricate a fitting to get a guage on it. Its not weather related, it started acting up last summer. I am thinking I have a valve issue, but where the heck is the valve? Just ordered a service manual but I was hoping somebody had seen this before and could help me along.

Pair-a-dice farm · Dec 10, 2009

I"m not at all familiar with the Kubota but it sounds like a plugged filter if it has one. If you don"t have a manual, check with a dealer. Any reputable dealer should be able to help.

Ken Macfarlane · Dec 10, 2009

If you build a little test rig to watch the pressure and close a valve to build pressure you should be able to diagnose the pump. Just tee'ing a gauge in won't show you anything, its an open centre system.

If the pump builds pressure the orbital is probably dead, the torsion spring broken or something stuck. The only 2 places I've seen the orbital on the Kubotas is down near the axle with a steering shaft or bolted to the firewall. Should be pretty obvious by following the hydraulic lines from the steering ram back.

keh · Dec 10, 2009

Not familiar with that tractor but tractors of that type usually have, in addition to the PS pump, a PS hydramoter that can go bad. Sould be located at the end of the steering column. Not sure how to check it unless holding a mechanics stethescope to it while turning the wheel back and forth with the motor running. I assume you have checked PS fluid level and check for leaks under load.
Any valve should be in the steering column.

KEH

Catskill Pete · Dec 10, 2009

Nope no filter on em, that would be to easy.

Catskill Pete · Dec 10, 2009

Thats what I was afraid of. Its located at the end of the steering column mounted on the firewall. A days work just to get to it! Times like this I miss my old 8N.

twopop · Dec 10, 2009

look on the pump for a large nut,maybe 15/16 or so .under it should be the pressure relief valve,which may be stuck open.there will be a spring and a plug under the nut.make sure the plug moves freely.the relief valves usually stick when a driver holds the steering against the stop.

Catskill Pete · Dec 10, 2009

Thanks sounds promising, I will check that out first.

Anonymous-0 · Dec 10, 2009

Pete check your e-mail .. 28 years KUBOTA experience here...sent you the answer Jerry

RodinNS · Dec 10, 2009

Not familiar with them.... but generally with hydrostatic steering, heavy steering equals a lack of pressure and wandering is the result of a bad motor or cylinder.
'T'ing a gauge in and steering against the stops should give you the relief pressure, or whatever pressure the thing is cabable of.
I would think there's a releif valve in there somewhere as well. That could be in the steering motor base somewhere OR in the pump. I've seen both on Ford's.... I've also found that with Ford's, most times the pump is bad.

Rod

Kubota M6800 steering

Catskill Pete

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Pair-a-dice farm

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Ken Macfarlane

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keh

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Catskill Pete

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Catskill Pete

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twopop

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Catskill Pete

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Anonymous-0

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RodinNS

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