The most typical places for a hydraulic leak are typically at the helm wheel, behind the wheel your hydraulic hoses go into the steering cylinder, its possible a line as cracked or is loose, check that before you have someone look at it, you will notice the yellowish liquid and it will look wet, there might be a small drip pool from the liquid below this location as well. Also check in the engine well where the engine is, the hydraulic ram itself might be leaking, yet again could be a loose line or a crack somewhere, on occasion the threads pull from these cylinders, it could also be bad seals inside the cylinder itself, but either way you will see some yellow fluid back there if it is leaking, especially when the boat sits. If neither of those areas check out it is possible that you might have a chaffed line inside the boat, but you would smell it in the bilge if its leaking there and should see an oily sheen in there or when the bilge pump turns on. The other option is you have air in the line and it needs to be bleed out. If your just adding hydraulic oil to the line by pouring it in that's incorrect method and could be the cause, you need to buy the bleeder tube that connects the sea star bottle to the steering column itself. It forces the air into the bottle as the hydraulic fluid goes in, also you can go on sea stars site and read how to properly bleed the system. The other option is pay someone, they will do it the best way by connecting lines from the helm to the steering ram and back again to completely bleed the system, I had it done last year, best $100 I spent, steering was super tight and responsive.
Before you have anyone look at it, have a peak yourself at the areas I mentioned so you know what it might be before a mechanic looks at it so you do not get robbed or talked into replacing the whole system, some guys are honorable and others try to make a quick buck where they can so always try and know what the problem is and what to expect so you can tell if something does not sound right in what they diagnose.
