2000 Champion 730A Issue is when you load the ends of the blade (either side) it spins the circle like there’s not enough resistance to hold it. I’m not weld versed with graders but from what I can tell from the main control valve there’s 2 pressure hoses going to what looks like a gear motor which has a drive gear underneath, from there that then ports the oil into 2 cylinders which work to turn there own drive gears. Could the motor just be internally bypassing? Machine is in rough shape. Thanks for any ideas
The hyd. component with the small gear underneath is the sequence valve for the circle turn cylinders. It allows the cylinders to turn the circle without binding. It is very important that it is timed correctly. There is a cushion valve for the circle turn as well that may be the issue. If it's not the issue it could one or both cylinders are bypassing internally. I wouldn't think the hyd. valve would be the problem.
Any idea where the cushion valve is? I didn’t see anything inline from that sequence valve to the control valve
For older models look at the manuals on the Sierra Park 730A web page. Should at least give you an idea. You could follow the hoses too.