Calling the two cylinder power steering experts

notyalc · Apr 22, 2017

So I have replaced the vane seals and all the orings in the steering assembly of my 830. The pump has been apart and had new seals fitted, gears and everything looked ok.
Tractor had been run for a while with no oil before I got it I think, I have looked at the valves, they were sticking, so gave them a polish and put back together.

Now the issues.

Assistance is ok at first start up when oil is cold, pressure about 800 psi on full lock. When it gets warm, pressure drops to 500 psi and assistance just about disappears. Have added washers to relief valve, can't get pressure any higher which is strange. The flow control screw is screwed pretty much all of the way in. Will that have any thing to do with the inability to generate any pressure?
Any thoughts please?
Pump or valve block?

buickanddeere · Apr 22, 2017

relief valve only controls the maximum pressure. A relief valve cranked to 1500psi will not make a tired worn pump exceed 500psi when the max pressure the pump can make is 500psi.

David G · Apr 22, 2017

I would agree with B&D, not achieving pressure while hot is not indicative of relief issue, it is of worn pump.

Bob · Apr 22, 2017

Did you check closely for wear/clearance between the tips of the gear teeth and the housing/center section and wear areas where the sides of the gears contact the outer sections when the pump was apart? NO gaskets were used between the sections, just a smear of gasket shellac. If there's lots of sealant there, or gaskets there from a previous repair attempt the pump might leak more internally.

In this era, I use a TINY amount of aerobic flange sealant when assembling them.

Rich Duane · Apr 23, 2017

The other problem in the steering unit is the spool valve in the control unit being worn.
What happens is the lands on the spool and the valve body erode over time allowing the oil to bypass the valve
back to the reservoir.
I have a fix for this problem. You have to replace the spool with a oversize spool and rebore the body thus
eliminating the leakage past the spool.
If you would like to talk about this call me at 410-643-2899
Rich Duane

notyalc · Apr 23, 2017

Hi Bob, I didn't take any measurements, as everything looked ok apart from the two sets of seals which were clearly damaged. I gave all part a light lap to remove any old gasket or sealer material. Gears were a good fit on the shafts.
Put it all together using a thin coat of permatex gasket maker.
It's not too bad a job to get it off and check everything....

I was just wondering if there were any other issues that I should look for.

notyalc · Apr 23, 2017

Hi Rich,
Thanks for the reply.
Being in the uk means a phone call would be expensive!...

Email would work for me if that's ok?

Bob · Apr 23, 2017

One other thing... what oil are you using? In the experience of many of us, genuine John Deere Two Cylinder Power Steering oil works the best, for pressure and smoothness of operation.

Rich Duane · Apr 23, 2017

My Email is open

Rich

notyalc · Apr 24, 2017

Hi Bob,

after reading all of the posts on here and elsewhere, i am using JD power steering oil....

notyalc · Apr 24, 2017

Hi Rich,

where do i find your email please?

Joe Way · Apr 24, 2017

(quoted from post at 02:27:39 04/24/17)
Hi Rich,

where do i find your email please?

Switch to Classic View in the red menu box at top right, then look for the Send Email link at the bottom right of Rich's last post.

notyalc · Apr 24, 2017

Thanks Joe, finding my way round here!

Calling the two cylinder power steering experts

notyalc

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buickanddeere

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David G

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Bob

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Rich Duane

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notyalc

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Bob

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Rich Duane

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notyalc

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notyalc

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Joe Way

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