I am in need of some tech support regarding my D4 7U. I was pulling a disc Tuesday and did about 14 acres. Everything was going well and it was a beautiful 75 degree day. The first two hours went great. As I was finishing up the field, it was getting harder to steer the tractor. When I was pulling uphill, the tractor was “drifting” to the left without any steering input. I was UNABLE to steer right to correct the drifting problem. It eventually was wanting to make a large circle in the field. By the time I pulled the pin on the disc and parked it, I had to push the left brake lever with all of my might just to get it to turn a little to the left. It would NOT turn right at all by that time, and I had to get creative to put it back in the barn. I have owned the machine for almost 10 years and have never made any steering clutch adjustments. I only put about 20 hours on the machine every year.  Do any of you have an idea about what is going on? 

I suppose he can start it up, engage in gear, and pull back on both levers simultaneously or individually to isolate the problematic side. Yes, adjustment either out, or worse, his release bearings collapsed and he would get the honor of splitting the cross shaft and steering packs. Fun job for any novice...Same deal, the proper tools make the job go easily.
***When he was on the phone with me, he mentioned lack of free play as well*** JM

Thanks to both of you Neil and JM. When things dry out, I will get up there and try to make the adjustment. 

I had something similar happen to a D6 9u. I had several 100 hours overs 2 or 3 years everything was good. Did a 7 acre field with a disc. Moved to another that laid so it was fastest to go up and down. Pulled one lever as I was headed up hill and it stopped moving. I managed to do the 2 acres and get it driven to the yard. Pulled steering clutches and nothing out of the ordinary until I started testing the springs. I don't remember the reading but way less than speck from Cat. I want to say about 1/3 of the pressure the manual say they need to be.

Just a big surprise it had been good as long as it had and just stopped after several hours of use one day. One of those too cheap to pass up as the tracks where near new and would of cost more than I paid for the whole tractor. But from other equipment in the yard it came from, you could tell maintenance had been very lacking for some time.

Lack of free play in steering clutches combined with slightly loose cross shaft bearings can make strange things happen.