hydraulic steering problem

[scrout]

I have a Terramite T6, 31 HP Perkins, mini backhoe.

Everything is run hydraulically on the machine.
Steering is a std 4 port/hose hydraulic orbital steering valve with one double acting cylinder on the front axle.

My problem is it turns right fine, but takes a LOT of steering wheel pressure to go left. So I assume the steering valve has blown a seal vs anything to do with the cylinder up front?

Thanks in advance.

 

[HydroTek]

Your on the right trail, depends on what kind of steering valve your machine has, some have poppets, centering springs, oil slots ...contamination or damage can cause your symptoms. Someone will need to disassemble the valve to be sure the cause. There are no seals inside the valve, except the ones to keep it from leaking to the outside world.

If you decide to take it apart yourself, be aware of small parts and where they belong Also Danfoss, Eaton, TRW, etc valves need to be timed internally (to keep from harming you with steering wheel oscillation)

The slot or pin must be aligned to the valley in the rotor section of the steering valve. Other than that ..keep it clean and work on a surface where you can locate dropped parts. Your camera or a note pad is your friend ..use it :thumbsup:
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PS: mark the lines ..simple white-out works fine or an etching tool.
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[wdchyd]

I have a Terramite T6, 31 HP Perkins, mini backhoe.

Everything is run hydraulically on the machine.
Steering is a std 4 port/hose hydraulic orbital steering valve with one double acting cylinder on the front axle.

My problem is it turns right fine, but takes a LOT of steering wheel pressure to go left. So I assume the steering valve has blown a seal vs anything to do with the cylinder up front?

Thanks in advance.

Be aware that ONE single double-acting steering cylinder has two different displacements internally, and will turn one direction easier than the other....This is normal.......If you suspect this is what's going on, then swap the two steering hoses temporarily to see if the conditions reverses.....

If it has TWO D/A steering cyls then it should be the same effort, both directions ......

Good Luck if the problem is the orbital steering valve, tough to see wear/damage internally by the naked eye, not a job for a noobie ......

 

[HydroTek]

Be aware that ONE single double-acting steering cylinder has two different displacements internally, and will turn one direction easier than the other....This is normal...

Umm ..no ..steering cylinders have the same displacement on each side.

I cant speak for a Terramite T6, but all others I know of use equal displacement, whether single or dual cylinders.

Swapping the steering lines is a good idea, there may be some binding of the steering linkage and this would prove it out. Have you "hit" anything with a front tire? With the engine off ..turn the steering wheel a little each way, does it return to center? does it "feel" the same each way?

wdchyd those are some nice looking beagles in your pic :thumbsup:
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[wdchyd]

Umm ..no ..steering cylinders have the same displacement on each side.



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Steering cyls would only have the same displacement on both sides if they have "Double hyd rods" rather single rod.....You have to take into account that the hyd rod on one side takes up some displacement (less volume)....same bore size, just less displacement

http://callisonsterramite.com/New/t9.pdf

Scan down to Page 2.6 Part# 25811 Power Steering Cyl

 

[wdchyd]

wdchyd those are some nice looking beagles in your pic :thumbsup:
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Thanx, I'm pretty proud of my furbuddies......I run them every weekend I can (this am included)......Great Hunting Dogs and they love the Kubota....

Take a look......

YouTube - Christmas Pass 2010

 

[wdchyd]

My problem is it turns right fine, but takes a LOT of steering wheel pressure to go left. So I assume the steering valve has blown a seal vs anything to do with the cylinder up front?

Thanks in advance.

If the P/S cyl seal was blown internally the orbital steering valve would turn & turn & turn & turn with no steering cyl movement, and it would be easy to turn the steering wheel as the oil would be by-passing from one side of the cyl to the other......

 

[HydroTek]

Actually my first response should have been to ask scrout if he had newly acquired this machine.

From the drawing, it looks like Terramite went on the cheap and only used half a steering system on their machines. With this setup it will turn easier one way than the other ..shame on Terramite for not using a proper setup ..either a double end steering cylinder or two single end cylinders. I suppose that is their way of cutting costs.

I had found the link to the parts manual, but the site was down when I posted ..maybe still a good exercise in steering system designs. Hmm ..wonder if Terramite uses 'regen'-'series' valves on the hoe? There is a good 'cut away' drawing showing the circuit reliefs in the valve sections.
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[scrout]

Thanks Wdchd and HydroTek,
Yes, this machine is new to me, but the steering was initially OK.
I was steering this thing with a rather large log on the loader, so somehow I think I overloaded something.
I think I might pop open the cylinder to take a peek at the seals.

Also, if I swap the lines from the steering valve, should it act opposite if it is a valve problem?
HydroTek, slots, poppets, springs, balls? Now I think I am a little apprehensive about tearing into the valve.......

 

[HydroTek]

If the seals are leaking inside ..your steering wheel would continue to turn without moving the wheel angle. Some steering wheel 'slippage' is normal, but should be the same each direction.

Reversing the lines would also reverse the steering action ..while not conclusive, it may shed light on the problem. Also raising the front wheels off the ground a little may allow you to check for bent or binding steering. Use the loader to lift the front end, just don't get under the tractor where it can fall on you.

Yup ..slots, poppets, springs, balls ..not a project for the faint of heart. Is that a Danfoss steering unit I see on your machine? (looking at the owners manual) They are pretty common in small applications, and really not that hard to repair, if that is the case.
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