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Hynautic hydraulic steering.

Discussion in 'Cabo Yacht' started by Jrms80, Dec 7, 2015.

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  1. Jrms80

    Jrms80 Member

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    While working in the aft bildge I noticed the hydraulic ram for the boats steering on the rudder shelf. In the engine compartment there is a canister which I guess is full of hydraulic fluid with a pressure gauge on it. This is connected to another fitting with several hydraulic lines coming out of it with an electric motor also tied into this hydraulic system.

    My questions are what turns on the electric pump and if the pump fails is this like losing power steering in your car and would I know it, would it be obvious or is there enough mechanical advantage with just the wheel without the pump? I've tried to find/googled a operating manual for my system but have just turned up the un-powered or the "manual" Hynautic manual. Is there a special name for Powered hynautic steering system and is there a way to confirm its all working as it should? The boat turns fine but it doesn't "feel" like power steering the thing is I don't have any idea what power steering on this size or any other boat should feel like. I have drivin a friends 1989 32 black fin express and the feel is about the same to me but I don't know if he has the same steering system.
  2. Capt J

    Capt J Senior Member

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    I'm taking a VERY educated guess here as I'm not looking at the electric motor, but 99% sure it is accurate. The electric motor would be the autopilot pump and that is what the autopilot uses to steer the boat left or right. When the autopilot is not engaged, the motor does not run and has no use.

    Your steering system is not power steering. Cabo put power assisted steering on 40' Cabo's and above generally. These utilized a power steering pump that was generally mounted on the port engine. Your system is simply hydraulic and either steering station is the "pump" and you turning the wheel is what moves fluid in either direction. The system utilizes the resevoir which should be 1/2-2/3 full (it should have sight glasses along the side of the body or a clear plastic tube that runs next to the canister to see the fluid level) and then pressurized with air between 20-30 PSI, and you can use a bicycle pump to pump it up. The system uses Seastar hydraulic steering fluid, but you can also use ATF transmission fluid or AW 32 in a pinch (or AW 46 but would make steering a little stiffer). If you have air in the lines, which the steering will be a little skippy (tension turning the wheel), the easiest way to bleed air out of the lines is to make sure you have enough air pressure and fluid in the resevoir and then crack the hydraulic hoses behind the tower steering station enough that solid fluid comes out. Do not take them off. Any air generally works it's way up to the highest station.
  3. Jrms80

    Jrms80 Member

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    Great info! Thanks! I'll revisit this steering system with this new info and see what's what. I'm sure you're correct. The small electric motor must be for the auto pilot.
  4. Pascal

    Pascal Senior Member

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    Couldn't have explained it better

    I would just add that I always keep a bicycle hand pump on board (unless the boat has a compressor) to top off the pressure of needed

    You need the air pressure to push fluid up the system to the helms A warning sign of low pressure or fluid loss is when your steering starts acting up at the flybridge but works fine at a lower helm or thru the AP since th pump is down low
  5. Jrms80

    Jrms80 Member

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    There is a gauge on my system that is showing 10 psi, I now know I need to fill this system as Capt J says to 20-30 psi. There are two air fittings, one by the gauge and one to the right of the gauge on the top of the tank. Which one gets the air hose hooked up to it? Thanks!
  6. Jrms80

    Jrms80 Member

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    Thanks, the manual says the fitting to the right of the gauge is the oil/air fill. I don't understand why there is an air fitting also on the fitting that the gauge is on in addition to the one shown in the manual. I now think the systems "bike" pump fittings can both be used to add air. They both must go into the tank what else could they do?
  7. Capt J

    Capt J Senior Member

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    It's possible. I usually fill the system to 35-40 psi, then when you remove the bicycle fitting you lose a little, then I press down on the shrader valve to get it to 30 psi.
  8. Bamboo

    Bamboo Senior Member

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    I've always kept the psi as low as possible where it still does the job it's intended to do. I fill mine up to 30 psi if the tower loses steering so I can bleed the tower station, then lower the psi to 10. I leave it at 10 and have no issues for a decade. If you leave it higher then it's more likely to leak; no need for more pressure if the steering is good.
  9. Beau

    Beau Senior Member

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    Just a guy who owns a boat, but for me I run my systems at the recommended pressures. If they leak at those operating pressures somethings wrong and you should fix it. Dumbing down the system, imo, only leads to a bigger failure when you least need it. In this example , you would have no ability to bleed the air down to a get home with just a drip.
  10. Bamboo

    Bamboo Senior Member

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    If that works for you then run with it! As a mechanic at Viking's south yard one of my primary responsibilities was steering system troubleshooting, R&R parts and proving the system. Many captains told me they run the pressure lower than the listed simply for the reasons I spoke of. Experience keeps a dear school and we all have slightly different lessons- but if they get us to the same place who's to argue? :)
  11. JWY

    JWY Senior Member

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    William - your post was excellent. You cited some significant qualifications backing your opinion and you wrote respectfully with open-mindedness while still supporting your original stance. Gentlemanly and well done.

    J
  12. RER

    RER Senior Member

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    I've alway's maintained Hynautic steering at around 2o psi. More boats than I can remember. Regular checks to confirm it's holding. Anywhere between 15 - 25 lbs I leave it alone.
  13. Capt J

    Capt J Senior Member

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    Really the only thing the pressure does is keep air from entering the hydraulic system. 1 psi of air pressure would work even. Both ways work. I prefer to keep my air pressure higher when I fill it, but as with anything with air pressure in it, over time the air pressure will slowly leak out. I usually fill to 30 psi, then let it get down to 15 psi, sometimes even 12 psi to add (over the course of a few months depending on the boat). I do prefer it higher so if you have a very slow leak there's more time until it all leaks out. But if you have no leak 10 psi would be ok too really.
  14. Capt Ralph

    Capt Ralph Senior Member

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    The Hynautic clutch & throttle controls do have a high air charge.
    I guess to keep the air/foam from forming in the Glycol.
    My Hy steering system seems happy @ 15psi.
  15. Capt J

    Capt J Senior Member

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    I think the Hynautic uses higher air pressure to actually push the actuators. Hynautic engine controls it's recommended to have 75-85 psi in the expansion tank.
  16. Marmot

    Marmot Senior Member

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    How's that work?
  17. captholli

    captholli Senior Member

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    Bueller? Bueller?
  18. Jrms80

    Jrms80 Member

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    Capt J,

    Thanks for explaining the purpose of the air pressure. I was expecting some change in the steering after finding the gauge at 10 psi and "fixing" it by pumping up to 30. Now I know why it feels the same. Obviously it's not a big deal in boat maintenance...
  19. Capt J

    Capt J Senior Member

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    You have fluid at 75 psi at the helm control, so when you push the lever from neutral to fwd/reverse it assists the pressure you're using to move the fluid (pump it so to speak) foward or aft at the actuator.