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Low steering presure with a new MCV (Multiple Control Valve) pump could be caused by a couple of different things. A blown o-ring between the MCV and the clutch housing would allow much of the oil to leak internally. This is the most serious because the steering has 5 GPM priority on this pump. Oil in excess of 5 GPM is directed to the brakes and TA operating pressure. Oil left over from the brakes and TA is used to lube the TA and most importantly the ring and pinion gears and differential bearings. I have seen many rear ends ruined because of a problem with the MCV pump flow. For a quick test of the system, when the steering is poor, do you have good assist on the brakes or are they just operating manually. You should notice a great change in the brakes between engine off and engine running. If there is little or no change you risk major damage to the ring/pinion and differential if you continue to use the tractor. If the brakes are good and you still have poor steering then there most likely is a valve problem in the MCV assembly. First place to check is the steering releif valve. It is located on the very bottom of the MCV above the larger of the two holes. Remove the tube that runs to the rear and connects to the fitting on the bottom of the MCV. You will probably lose about 5 gallons of oil out of the port so have a couple of clean buckets on hand to save it in. Remove the fitting and pull out the relief valve. A needle nose pliers usually works here. A blown oring on the this valve is more likely than a problem with the valve itself but I have seen broken springs. If that is OK then you probably have a stuck flow divider valve. At this point it is best to remove the MCV and go through it cleaning everything and replacing all the orings. You really need a manual from this point on.
IH says you cannot repair a flow divider valve when it is scored, you must replace the whole assembly. I replaced the MCV if the tractor was still in warranty. Out of warranty units I repair by getting the stuck valve out of the MCV and polishing the valve and the bore it goes in. I made a tool out of a bolt a little smaller than the bore and cut a slot in the end that would hold some 400 wet/dry paper. The other end I turned down to fit a 1/4" drill. I used the drill to polish the bore and hand polished the valve. If you know what to do you can do it without taking the MCV off the tractor.
The reason I was given from IH techs for not being able to repair the flow divider valve was that it would upset the 5 GPM flow (3 GPM on 1066 and older) for the steering. This flow is determined by the orvice size in the MCV, and not the flow divider valve. The flow divider valve is pilot operated by the oil passing through the orvice. Any leakage past the valve should just move the position in the bore to compensate for the leak and everything should work the same. (Excessive leakage woukd lower the flow/pressue to the steering.) When I ran this by the IH regional tech guy I never got an answer back. I have repaired dozens this way and outside of a couple I had to do again (lets keep that oil clean) I never had any other problems.
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