I just had the 4 hydraulic cylinders repacked on my B 219 front loader. I drained out the hydraulic fluid, cleaned out the filter screen and replaced both low pressure return lines and raplaced the pressure line from the pump to the spool. I filled the hydraulic tank up to specs, the question is: can I just start the tractor and let it build up pressure or do I need to purge the system first?? I just want to make sure before I damage anything. Thanks!!