Jim, the faulty steering valve is the steering controller, correct? I found a diagram of the steering system online and it looks like, since fluid is getting to the hoses which connect to the cylinder from the controller, that something in the controller is failing to control direction of flow. If my understanding is correct, when the wheel is turned right then flow to the left side should be blocked and that is a function of the steering controller. Am I right in assuming that if the cylinder seal was bad, that fluid would have blown out the cylinder fitting and not the hose end?
Much appreciated,
Ben