Here is a post from a few years ago from Bernard Le Mechano:
Hi TDK, on the 574 tractor, like 74 and 84,85,95 series, it's a Danfoss steering valve. You have to remove all the valve from the tractor and open the valve to change the seal. Some part inside have to be timed, so if you haven't opened a Danfoss valve before, good luck. Best way, take the valve to a CaseIh dealer and ask them to change the seal. To install the seal, you need a special tool. Be careful when you remove the steering wheel, don't blow on the shaft with a hammer, remove the wheel with a puller. I have done many seal changes when I worked for CaseIh dealer.