Unit has developed a settling problem in the Carriage only. Not the tilt. Put one new kit in center cylinder to solve external leak and address settling. No improvement. Replaced The main control valve, still settles. When raised part way the carriage will settle about 1" in a minute. If the carriage is raised to the top and deadheaded it will not settle. So do not think it is a leaking piston. What
could be causing this? Air in system should have worked out by now as it has been used a month.