All you have to do is have your steering fail once to find out how important it is to have the right hydraulic fluid. We bought a new boat with hydraulic steering. A few months later, I checked the reservoir and it was low. There was a Teleflex steering fluid container with fluid in it that came with the boat, and so I topped up the reservoir.
Over the next few weeks, the steering wheel
became a bit harder to turn. I thought it might be growth around the rudder
, as I hadn't cleaned the bottom for a while, and where we were, it built up quickly. Leaving an anchorage a few days later, my wife suddenly said, "I can't move the wheel!" I went back from the bow to the wheel
, and sure enough it was very hard to turn the wheel. I gave it a yank and suddenly the wheel had no resistance whatsoever. Whoops --- had we lost
steering? Yes we had! A hydraulic fitting in the steering lines had given way.
We survived, although getting reanchored safely with no steering was a bit dicey.
The problem was with the hydraulic cylinder that drove the rudders (we have a cat - 2 rudders). It had seized up. After being removed, it was impossible to move the rod. My hydraulics guy took it apart and said the nylon bushing that held the cylinder o-ring had swelled up and completely jammed the cylinder. It took him 45 minutes just to get the piston out.
We later looked at the "Teleflex" fluid and determined that it definitely was not the real thing. Wrong color; wrong smell. My mechanic
thought that it was brake fluid. Since the prior owner spent most of his time in the Caribbean
, I think someone may have gaven him auto or aircraft brake fluid to top up his hydraulics because they didn't have the right stuff. Brake fluid has to survive very high temperature and has all sorts of nasty additives to do so. If you have ever messed with brake fluid, you know that it will eat the paint
right off your car if you spill it. It evidently also eats boat hydraulics.
Let me tell you that there is nothing like suddenly loosing all steering. I used to think that Teleflex hydraulic fluid was expensive, but no more. Go with the real stuff---whatever your manufacturer recommends--- don't cut corners. There's no telling what plastic parts
in your system may not like some ingredient in non-standard fluid.