I have a 621b case loader that is hard to steer any thoughts?
If you have a gauge you could check the pressure, the front section of the hyd pump is the steering and the tube with the quick connect is where you check the pressure on that section. With the gauge hooked up and turning at the stop it will read around 2500 psi. at The tube runs to a small valve (flow divider, about the size of your hand with three lines to it) it gives flow first to the steering system. In that valve there is a spool and spring that controls flow, and you will have a plug fitting 1/2"/9/16" wrench size that you screw out and there is a filter inside that you can wash out and check for trash. The cylinders can be checked by using plugs on one cylinder at a time and checking for bypassing oil or even air pressure to one end with both lines unhooked to the same cylinder. Care must be taken to use the safety lock bar to keep it from turning in the pinch point area, air and hyd oil can be expelled with great force so use caution while testing. About how many hours on the machine, have you owned it since new, do all loader functions work along with good cycle times.
Steering with machine off steering wheel should not turn . If it turns with out heavy effort system has leakage. Block off cylinders first one at a time and check again