Freeing Brass-Stainless corrosion

[Nosmo]

We have a rudder on a 4x with a corrosion problem. The shaft of the rudder is stainless and is corroded into the brass sleeve that should be fixed to the boat. We can still steer but it is not smooth because the brass tube turns with the stainless shaft. Is there something good that dissolves this corrosion?
I know ammonia works well on Aluminum corrosion. I'm guessing that won't work. Should I just use Liquid wrench or is something better?
(An internet search didn't find anything useful yet--maybe I'm just impatient._
Thanks.

[sul]

When I ran into this a few years ago, I was told to try white vinegar and/or hydrogen peroxide. I was pretty surprised, I didn't think stainless and brass were subject to electrolysis. I assumed bad quality stainless, perhaps.

I had little success with my chemicals, maybe you'll have more.

I removed the unit since the brass tube was loose anyway, and was able to muscle the rudder post out with the help of a vice and hammer!!

found a similar diameter stainless tube, cut to size, and installed.

[Nosmo]

Thanks sul,
Talked to our local machinist who said, the corrosion might be all in the brass and the stainless is likely fine. Thought we could try liquid wrench, but he uses an industrial grade version called "Kroil". According to google, the "galvonic series in seawater" shows that brass and stainless are pretty fairly compatible but there are various grades of brass as well as stainless. Bronze looks better but Carbon Fiber looks much better yet. McMaster has various diameters of carbon fiber tubing for reasonable prices so we may choose that route.

[sul]

Right, that was the case. The brass was corroded, but the stainless was fine.

[Nosmo]

It was just the brass corroded. The stainless is fine. Once we removed both tubes from the boat it wasn't too difficult to get them apart. Cleaned, polished and put them back in, until we get a new brass piece.

[JD]

Check that the shaft of the rudder is not bent. This a problem on some boats, esp. Vespos when the crew whacks the yoke on a trailer crossbar when center-loading. The tube and rudder shaft bind. Once the sleeve starts to spin, you have to remove it, clean it, let the area dry and reglue it with epoxy on the bottom and epoxy putty around the support areas inside the deck. Otherwise it'll leak water - again, esp on Vespoli's. Lots of people think that the Vespo fins are the source of the leak and silicon the H out of the mating surface of the fin and skin, making a huge mess that attracts dirt and is difficult to remove (use plumbers putty for this job). It's more common that the rudder tube is loose and the source of water intrusion.