Let me put it another way.
If the rod end is extended and up, and a load is pushing down on the rod, and the cyl is closed off, could air get by the rod seal.
Excerpt:
Air can enter the system through a cylinder rod seal.
Vacuums in excess of 20 inches of
mercury have been recorded in systems
without anti-cavitation check valves. This is
enough to force dirt particles past the shaft
seal into the system with the air.
When you raise a full bucket in the air, and it is down on the ground within hours or overnight, and if the cyl is sealed off by a good loader valve, what would you say is the cause of the bucket descent?
If you say piston seals, that means that the fluid transferred from one side of the piston to the other side.
Sometimes, I don't always understand what I read or hear, so even at 74 yrs I am still trying.