I have a 550 with power steering. I use the tractor daily and the power steering pump recently quit and the steering cylinder leakss. The steering pump is mounted behind the generator. Power steering parts seem to be hard to comeby and expensive. As a quick fix to keep going, I am thinking of converting the tractor to negative ground and installing an alternator with a double pulley, then I can drive an automotive type steering pump off the alternator. Rigging up a bracket for the alternator and pump looks pretty straight forward. Has anyone had any experience with this?  Also , is there any steering cylinders that are a close fit?