I don't think that's a hydraulic problem if it's loose when not running. Take 2 people and check it by one person wiggling the steering wheel back and forth. The other person should check where the arm comes out of the steering box down below the steering wheel, then between the 2 rear wheels there is a bellcrank that the tie rods connect to that has a big pin and bearing that it rotates on. That's usually the problem. Then check the tie rod end that go from the bellcrank to the wheels. Or, jack the back of the machine up and grap one of the wheels and wiggle it and look at the tie rods and bellcrank to see what's loose. That's the best way to check.