Found A Whatzit, Sorry no picture...

that I could figure out how to post on here, anyhow. I was looking at the CaseIH parts search & ran across a special auxiliary junction block, for the hydraulics on a 400. When searching, look for 400-Series Farmall Gas Trctors, Hydraulics & it"s under section 358 Hydraulic System, Hydraulic Equipment, Special, etc. What"s it for & where does it go? Might it be used for a mounted cotton harvester or corn picker? An inquiring mind would like to know.

Thanks,
Mike

<a href="http://s140.photobucket.com/albums/r16/Wardner/?action=view&current=001CSIH-30815.gif" target="_blank"> </a>
For those who didn't go to CaseIH.com, here is the item. It appears to be nothing more than a Tee. No separate controls for one side or the other.

<a href="http://s140.photobucket.com/albums/r16/Wardner/?action=view&current=W-400054.jpg" target="_blank"></a>
Here is what I made today. The block on the left will replace a similar plate on the right (no ports). Fittings go to the side because there is no room otherwise. The similar plate is the last piece in the hydraulic valve stack. It is a dead-end. I will place the new part in its place. Hose will run to the piece below.

<a href="http://s140.photobucket.com/albums/r16/Wardner/?action=view&current=W-450.jpg" target="_blank"></a>
I will attach three more valves to this inlet plate. I will take the current end plate and use it as an end plate for the new valve bank. I will bolt up the Farmall levers to the new valves and be happy as a pig in oil with six hydraulic circuits. I will mount the new valve bank near but to the right of the existing valve bank.

Are you adding IH valves to your 400? If you go with six valves you may have to enlarge the orifice hole size in the screen to get the system to stay off of high pressure. The orifice has to be able to pass more oil through than leaks past the spools when the valve are in neutral to be able to move the unloader valve to standby pressure.

Thanks for the tip, Owen.

Yes, all the valves will be IH as found on '55 to '61 models. When you say "enlarge the orifice hole size", would that be in the regulator?

Is this a good idea or am I heading for trouble?

(quoted from post at 23:30:36 07/20/10) Thanks for the tip, Owen.

Yes, all the valves will be IH as found on '55 to '61 models. When you say "enlarge the orifice hole size", would that be in the regulator?

Is this a good idea or am I heading for trouble?

Click to expand...

The hole is in the screen assembly in the regulator block. I see the 400 parts books call it a regulator valve, later tractors called the same type of valve an unloader valve.

I'm sure you know that the hydraulic system is a closed center system but uses a pump like the open center systems. To make it work there is an regulator valve that drops the hydraulic pressure to a standby pressure to about 60 PSI. The little spring behind the regulator valve pushes the valve open. Hydraulic pressure on the other side of the valve, which is more than the spring pressure, pushes it closed and the pressure will rise until the safety (relief) valve opens. There is an orifice and screen assembly in a passage that runs from the pump side of the valve to the spring side. This orifice allows oil to flow through to make the hydraulic pressure equal on both sides of the valve. Since the pressure is the same, the spring is enough to push the valve open to dump the oil flow back to reservoir. To make the regulator valve close and cause the hydraulic pressure to rise there is a passage from the spring side of the regulator valve that goes to each spool in the auxiliary valves. In the neutral position this passage is blocked off in each valve allowing the regulator valve to stay open. When the auxiliary valve is moved to a demand position, the spool is moved to allow the oil in this passage to dump to reservoir. Since the spool will dump more oil than the orifice will allow through, the hydraulic pressure on the spring side of the regulator drops and the valve is pushed hydraulically against the spring to the closed position. Oil pressure rises in the system to the level needed to move an attached cylinder or open the safety valve, which ever is less.

Since the auxiliary valves are spool type valves there is some leakage past the lands in the control circuit. As long as this leakage is less than the amount that the orifice will allow through, the regulator valve will function to put the system in standby pressure mode. If the orifice screen becomes restricted or plugged not enough oil will flow through and the system will remain on high pressure. Excessive leakage past the auxiliary valve spools will also cause the system to stay on high pressure.

Since you would be going from three spools to six it is quite possible that the leakage will be more than the orifice will allow through and the system would stay on high pressure. Worn valves can be compensated for by enlarging the orifice hole in the screen assembly to allow more oil through. The down side is that any oil that is going through the orifice is not available to the auxiliary valves to do work.