Tractor Repair: 1066 steering, ball point pen, battery cables

Question
Hello Arnie,
I am working on a 1976 1066 that was involved in a fire earlier this yr. I have it running again. I don't have any of the wiring back on it yet other than the battery cables. The current problem is that it has no power steering. The TA seems to shift and I have brakes. So I assume that pump is ok since they work(and I took the plug out of the Flow control orifice and it shot oil all over).
From reading your past answers, I assume its something in the MCV valve. The tractor didn't get as hot on the left side except for the rear tire burnt enough that it discolored the paint on the MCV cover. I have the service manual for the tractor(GSS-1431-1)so I have diagrams and names for all the valves within the MCV if you want to throw out specific names. I was wondering if there is something specific I should look at to fix the problem or if it's a crapshoot of what the problem actually is? The power steering worked fine before the fire.

Also, can I check the valves involved with power steering inside the MCV without taking the MCV off the tractor?

Thank You,
Blane


Answer
Hello,

  Yes, the steering, brakes, and TA all operate from the same pump located inside the speed transmission, mounted to the inside of the MCV valve.  If the TA shifts OK, then we can assume that the pump is supplying pressure.  There is a steering relief valve, steering priority spool,( sometimes called a flow control spool ), and a sump check valve in the MCV that all need to function properly for the power steering to work.  The first 2 can be checked without removing the MCV, but to service the sump check valve you will need to remove the MCV because it's between the MCV and the transmission housing.  The sump check valve is plastic with a small spring similar to a spring in a ball point pen, so it would certainly be possible that the plastic melted or distorted from the heat.  There is an o-ring on the body of the steering relief valve , and o-rings and gaskets between the sections of the MCV that could have been damaged also.  The priority spool could be stuck.  Check the easiest things first and if you have no luck, then remove the MCV and inspect all o-rings, gaskets, and the plastic sump check.