Steering fluid vanishing act?

[snal]

For the second time, I've had to add fluid to my steering system. The need is evidenced by "notchy" steering felt at the wheel, and slow steering response. I had to add about 1/3 quart twice now (within a year). I can find the slightest leak anywhere! Any ideas?

[Sea Wolf]

snal-

I think the"notchy" feel is the little pistons that are in the front steering mechanism operating as you turn the wheel. With the system low on fluid, the response and feel are different. Air at the front end (helm) gives it that on/off feel to the compression and movement of the air/fluid combination. Solid fluid feels smooth.


So where is it going?

If you've checked everything out for leaks, it must be evaporating, or, more probably, leaking and evaporating back at the steering slave cylinders (shafts) and then evaporating. Air could enter the fill cap up front as fluid is lost out the back, causing the "notchy" feel, and causing the need for fluid replacement.

You can smell hydraulic fluid, so it has vapor pressure, and will evaporate, though slowly. You might not notice it, and some may drip overboard if your moored or in a marina.

Is the boat kept in a warm climate, in the sun, or someplace hot?

That's my guess...so far, at least!

Joe.

[thataway]

Probabaly having minute losses as Joe says, through the seals on the ram.
Ibelieve that these pumps are a wobble plate pump with 5 cyl and that is what you are feeling. I had to tear down one of the larger pumps on one of our larger boats. Just keep the fluid topped off. Some systems have a resivoir and they have to be kept topped off and pressurized.

[snal]

Thanks guys!
The boat is kept in a non-climate controlled garage, that likely does get quite hot in the summer.
We've had to add fluid twice in the 18 months that we've owned the boat.
It's a Seastar system, fill point at the helm.

[Albury23]

I have the SeaStar system. Sounds like the hydraulic fluid level dropped enough to introduce air through the fill hole. Once air gets into the system it will continue to give inconsistent feedback even after topping off. You probably need to perform the fill / purge procedure to rid the system of air. The procedure includes a pressure test that you can use to identify leakages sites. Depending on your system, the following reference may help -

http://www.seatechmarineproducts.com/download/Seastar_Boat_Steering_Technical_Reference.pdf

[snal]