Hydraulic oil question

[Johnherbert]

I have an issue with my timber trailer hydraulics. Over the winter months it’s stored in a barn and brought out again in the spring when drier conditions allow timber extraction. The hydraulic oil become contaminated due to condensation while inactive. So is it better to drain the system and leave it empty or top it up full to the limit and take out the excess prior to use. The tank is plastic.

[dig-dug-dan]

Drain it if its stored for such a long period of time

[openspaceman]

15 minutes ago, dig-dug-dan said:

Drain it if its stored for such a long period of time

I've never done that, I think my first move would be a water separator in the return line.