[Bo322]

I purchased a 1977 42 about two years ago. The boat was in nice shape and turn key ready to fish. I have been working steadily on her making improvements the whole time. Last spring I hauled the boat for a "two week" bottom job. Five and a half months later everything was new from the rub rail down.......
I have been focused on the interior ever since. While I was removing some old wiring I developed a leak in one of the 1/4" copper hydraulic steering return lines. It would be easy enough to fix by cutting the leaking spot out, double flare the line ends and use a double male coupling. My concern is much of the line is green and corroded and I am going to replace both return lines. Has anybody done this and what recommendations do you have regarding the type of line I should use? I have a pressurized system that generally stays around 20psi. I have been told they make a plastic line, similar to trim tab hose, that will work.
Any advice would be greatly appreciated.

[Marmot]

If it failed because it was corroded you would just be wasting your time. Copper tubing isn't so expensive that you should try and salvage such an important system.

[Bo322]

Originally Posted by Marmot

If it failed because it was corroded you would just be wasting your time. Copper tubing isn't so expensive that you should try and salvage such an important system.

Thanks Marmot, I agree with you, that's why I'm replacing them. I am curious if anybody has replaced their copper lines with some other material in order to avoid the corrosion issue.

[Marmot]

Take a look at the high pressure nylon tubing. We used to use that for hydraulic lines on deep diving systems and it worked very well. Look for Nyflow or Nylaflow or something like that, they have working pressures up around 1,000 psi and burst pressures of over 2,000 for 1/4 or 3/8 so should work well for your steering system. The fittings are simple and easy to use as well and don't leak so there are definite advantages.

[jhall767]

They make a nylon tubing for hydraulic steering. You can buy it in bulk. Make sure whatever tubing you use is rated for the correct psi. You mentioned 2 return lines and 20 psi. Often there is only one return line and two pressure lines. The 20 psi is no where near the required working pressure for the tubing which is usually around 1000 psi. It would not be a good thing if a steering line blew coming through an inlet.

[Bo322]

Thanks for the info guys. I'll do some poking around and let you know what I come up with. I know what you mean about those inlet "surprises" jhall.
Bo

[Capt J]

I've had very good luck with the Seastar black tubing and it's easy to run and work with, then again so is copper and it lasts a long time as you well know. The entire copper line needs to be replaced.

[RER]

Yeah... replacing only the blown section just pushes the problem down the line. Literally. I've replaced copper tube with marine hydraulic steering hose... it's black with a ships wheel logo about every six inches or so. I think it's Wagner. Also, re-routing the new line to be accessible under the cockpit as opposed to the original run which usually is not.

While it's disconnected and drained... a good time to rebuild the helm pump, auto pilot, and hydraulic cylinder.

[Bill106]

Parker Parflex MSH5-5/16" OD, 1000psi WP or MSH6-3/8" OD, same WP. Use the larger size if you can snake it back through your chases. Lewis in your area carries it and the brass SAE -6, field attachable fittings that will screw onto your existing flare fittings.