How severe is the tendency to turn?? If it's not adjustments for the steering clutch and brake you may have a problem with undercarriage alignment.
Another thing to look at is the size of the sprockets. If there's a fairly good one on side and a badly worn one on the other side, it'll drift to the side of the smaller worn one. If you pull the right side steering clutch and use the the right brake and it turns to the right, it may not be the left steering clutch at all. It also could be worn bushings in the frames or a bent cross shaft. Check the front idlers too. .if they're loose or missing parts, that could be another reason.