soft top hydraulic fluid ???

[Smurfskier]

So I was having issues with the top going up. Going down was no problem so I finally decided to take the top off and replace the motor. Removed the top to find the resivor for the hydraulic pump is empty and it l can see two bad copper crush washers on one of the fittings that is wet with fluid. So my question is what kind of fluid do I need to purchase to refill it and how much do I need to put in it. searched without any luck.