My son and I figures out what we think is the easiest way to place the detent balls/spring on spool valves. We took an ink pin top that had a hole on the top of it, put it in a long screwdriver. then placed valve on a piece of something so the end where the balls/spring go is off the table. we placed one ball in one hole with spring and brought collar up at an angle to hole ball, then turning that side down and putting other ball on top exposed spring and pushing ball into hole while pushing collar over the balls, worked excellent 2 times.
