Joystick pilot control

I know this has been talked about before, but can not seem to find what I need to know. I have old Asv Rc 30, I just use it around my property for snow removal and gravel driveway. Its in good shape for age and has had few issues. I notice by forward direction pintle on control is sitting lower than the other 3. Its not leaking, (yet) and works well. Not sure if it being lower is causing unseen problem, but i think it should be the same height, for proper syc with other valves. I was thinking of resealing the 4 pintles, and finding out why forward is lower, (spring Im assuming). But as I read on this form parts are hard to find. Its uses a Cat 172-6838 valve, which changes up to a 193-8356. Am I wasting my time trying to find a kit and or springs, I can buy new of course, from local dealer, but its pricey. I love this machine, and don t mind putting some green into it, but I hate wasting time looking for parts if there isn t any. Does anyone know were, or who might still have parts. Thanks