Leaking cylinder on implement : is it common when stored for a long time with no oil pressure?

[mangler]

I have a flail mower with a a hydraulic side adjustment. I recently realized the cylinder is leaking (at first it was user error, i had the hydraulic lines pointed down so they just leaked out of the ends). But even after I corrected this it kept leaking out in the garage, now I am convinced the cylinder is actually leaking.

Not a hydraulics expert, is it common for cylinders to leak when the pressure is low? I figure the lines almost emptied out, so there was probably a mixture of oil and air pockets in the lines when the cylinder started leaking. Is there a chance it will "seal back up" when I apply actual hydraulic pressure in the lines/reconnect?

 

[Snobdds]

Cylinders should never leak.

Hydraulics systems will leak down with no pressure.

For example, the backhoe on my tractor will bleed down and be on the ground by the following morning, normal. However their will never be a puddle of hydraulic fluid on the ground.

 

[Harry in Ky]

Agreed the cylinder should not leak. The hoses though, are a different matter. The male tips are prone to leak when left dangling like that. Some more than others, but none can be trusted. It always helps to tie them up so the tips are higher than the cylinder.

 

[Tinhack]

Also note that if you use those rubber cup covers, position the hoses so the cup is on top of the hose end. After a while, the rubber covers deteriorate and allow water to seep in if facing down.