580c, steering: when started, wheels went hard to left. no response with steering wheel, but has some resistance when manually turning wheel

[1_pop-pop Tweed]

bought 580 c with steering not working. low pressure at pump. New steering pump, > 1800 #. disassemble, & inspected control valve. rebuilt steering cylinders. When started, wheels went hard left...When manually turning steering wheel, some resistance, but no response with wheels.

 

[Harry in Ky]

First mistake. "disassemble and inspect control valve".

Most hydrostatic hand pump/steering valves are not really "homeowner serviceable". Depending on just WHAT you took apart, it's very easy to get the internal timing messed up. When that happens you get problems as you described. Start the engine, the wheel takes off in one direction or the other and wont stop until the steering bottoms out and the pump relief kicks in.

Your choices are few.

Remove the valve again, find a manual covering that particular valve, and hope you can figure out with that just how to get the thing back in time.

Take it to a hydraulic repair shop and pay them to do it.

Replace the valve.