I bought this 1456 three years ago as a restoration project. The tractor needed overhauled and needed some rear end work. Every winter we have worked on it to get it fixed up and after each winter we would use the tractor to make sure that we fixed the issue. It was suppose to get painted but I got it out of the shed and when you started to turn the steering wheel it would suck air which causes the steering wheel to catch. I talked to a few good friends who work at area implement dealers about the issue and have done everything they have told me to. I have taken the Multiple Control Valve off and put all new O-rings, Gaskets, and a new pump on it and it still does it. I've had the valve out of the bottom of it and replaced it with a different one that I know works and also have the oil filled an extra gallon. My next option is to take the hand valve off the back of the steering wheel. Before I go and do that I am hoping that someone else can relate to this and tell me what they have done to fix the issue.