IH hydraulics

Hayfarmer · Nov 17, 2012

I am more familiar with JD hydraulics but I have a SMTA also. JD went to the closed center hydraulics with New Generation tractors(mostly). Did IH change to closed center also and with what series of tractor?

IH fan · Nov 17, 2012

(quoted from post at 14:25:31 11/17/12) I am more familiar with JD hydraulics but I have a SMTA also. JD went to the closed center hydraulics with New Generation tractors(mostly). Did IH change to closed center also and with what series of tractor?

I can't answer your question as to when/if IH changed, but a closed center system requires a pump that will drop to at, or near a no flow condition, generally just enough to allow a low sensing pressure. Most use a pressure or pressure/flow compensated pump which cams the swash plate of a piston pump back to neutral. Then when a valve is opened in the system, the swash plate is rotated or cammed to an angle to increase the flow. In a presure comp, it generally cams to a set angle, or all the way to a stop... in a p/f comp pump, the angle will vary according to how much the valve is opned. If anyone knows what type of pump is in their tractor, it should tell you if it's an open or closed system.

Jim Becker · Nov 17, 2012

As far as I know, the first closed center systems IH used were the Touch-Control systems on the Cub, Super A and C. The version on the Super A was probably first in 1947. The pump was a simple gear pump and the pressure/flow control was inside the main Touch-Control unit.

rufus80 · Nov 17, 2012

All of my '66 and '86 series are open center. IH changed over to a closed center system real late in production of the '86 series and the '88 series were all closed center.

IH fan · Nov 17, 2012

(quoted from post at 18:46:36 11/17/12) As far as I know, the first closed center systems IH used were the Touch-Control systems on the Cub, Super A and C. The version on the Super A was probably first in 1947. The pump was a simple gear pump and the pressure/flow control was inside the main Touch-Control unit.

A valve external of the pump was also an option for a closed center system, but as pres. comp and p/f comp pumps became available, I believe those valves pretty much became obsolete. We made a pressure comp valve, maybe as late as the mid-late '80s, but don't think we did after that. Maybe some companies did though. We made a lot of gear pumps for IH, but don't know about piston pumps.

Jim Becker · Nov 17, 2012

We talk about a lot of obsolete equipment on this site. I was attempting to answer the original question, which I interpreted as IH's first use of a closed center system regardless of the specific pressure/flow control mechanism.

charlieu · Nov 17, 2012

Most people do not relize it but, the 300/350-400/450 460-560 series of tractors used (Hydro-touch) close center hydraulic valves. There are also others that used this system.

That is why so many people have trouble with the pressure regulator valve with the little orfice with the screen on it that likes to plug up. Oil flowing through this orfice is actually used to open the dump valve that opens up to allow pressureized oil to flow back to the reservoir when the hydraulic valves were returned to netural.

Red power magazine did a story on this hydraulic system a number of years ago. They explained it very well. I wish somebody would do a story on how the power steering was added to the hydro touch system explaining in detail how all the valves work.

I will have to look back in some of the old magazine to see if I can find the story that the Tractor DR. did. I hope this helps. charlie

IH hydraulics

Hayfarmer

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IH fan

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Jim Becker

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rufus80

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IH fan

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Jim Becker

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charlieu

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