The nose gear door on my 320 has started this strange behavior of
gradually moving towards the closed position over a period of days with
plane in the hangar.  I think the design of the system is per the
Lancair build manual.  Only the up side of the actuator is plumbed into
the hydraulic system.  The down side is open to the atmosphere and
down-force is supplied by a "coil-over" spring on the actuator.  The up
side hydraulic line goes through a sequence valve actuated by the gear
being fully retracted.  The only thing I can think of is the sequence
valve is leaking pressure to the actuator, but where would that pressure
come from?  Isn't the up side of the system depressurized in the
gear-down mode?  Is down side pressure leaking to the up side somewhere?

Moon Dog,

 

Stop flying in the cold weather and then storing the magic carpet in a heated hangar.  I think your think is right - the sequence valve is leaking (or the down side is leaking to the upside), the hydraulic system is warming up and expanding and (or) the plane is parked during beautiful weather generated by a local high pressure and then, after hangaring, gloom arrives via a nasty winter low accompanied by ugly overcasts - thus the open "down" side pressure is lessened and - voila! - just like the water level in an unused toilet after pressure changes.

 

Has the ghost of Christmas Past been bothering you lately?

 

Grayhawk