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Autopilot noise at helm

Discussion in 'Technical Discussion' started by TahoeJohn, Dec 21, 2020.

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  1. rtrafford

    rtrafford Senior Member

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    Sounds to me like his whine is intermittent, meaning its not originating from the helm pump or the engine pump, not unless it's constant bypass bleed from the helm pump via the engine pump flow. But he should be able to replicate the whine with the engine off and use of the pilot pump only, in a quiet environment. Using the pilot helm control to make the pilot pump work.

    But what I see of his plan he's off to a good preventative start.
  2. TahoeJohn

    TahoeJohn Member

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    Tahoe VIsta
    Yes, the whine can be reproduced with the main engine off.

    Thanks again for the help! I'll get started on this project and report back...
  3. DOCKMASTER

    DOCKMASTER Senior Member

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    Ketchikan, Alaska
    Some might say rebuilding the pump is an unnecessary first step. But I agree with your approach. For $180 you get piece of mind and hopefully go thru your system once and be done. Replacing the filter, fluid and bleeding the system will be a bit tedious. I certainly wouldn’t want to do that and then find out you have to rebuild the pump anyway. Then you would have to bleed the system all over again.
  4. rtrafford

    rtrafford Senior Member

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    While I agree, if failure is happening at the pilot pump, you'll note some issues in the helm pump rebuild. I think it's an overall good preventative first step that narrows the issue down to, eventually, the pilot pump. In fact, as you've noted the tediousness of the overall project, if there is a good, working spare pilot pump on board, I'd swap that during this clean out process. My hunch is that his whine is the pilot pump on its way to the shop. But cleaning everything, refreshing the helm pump, swapping the filter and flushing the lines leaves you in a very good state of mind with regards to the steering. Note to self: drop the rudders on the next haul to check bearings and seals. Well, not to self because I just went through all of this.
  5. DOCKMASTER

    DOCKMASTER Senior Member

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    Ketchikan, Alaska
    Is your pump 12v or 24v? If it is 24v and you decide you need to replace I’ve got a good condition used one you can have. Just cover the shipping cost. I removed it last year when I got rid of the Hynautic system and installed my all electric system. For that matter, I have the complete Hynautic system if you need other parts. I also had pumps on both engines so you would have power steering if only running one side or the other.
  6. rtrafford

    rtrafford Senior Member

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    Holy smokes, by all means be on DC auto pilot pump control. Dad always told me, **** the toilet and AC. Take care of the ice maker and the auto pilot. Never want to be without.
  7. TahoeJohn

    TahoeJohn Member

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    It's 24VDC. PM sent!
  8. d_meister

    d_meister Senior Member

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    San Diego, CA.
    Where is the AP pump? You differentiate between that and the engine driven hydraulic steering pump. If the AP pump is anywhere near the helm, that's where the noise is coming from. Flex hoses may help, but I've heard the pumps resonate through the structure they're mounted on.
    If the helm were bypassing fluid driven by the AP pump, the wheel should be turning as the AP actuates.
  9. TahoeJohn

    TahoeJohn Member

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    The AP pump is mounted on the wall of the engine room. It's 2 decks below the helm but connected via 3 hard copper lines. The AP pump is teed into the three lines coming from the helm, labeled P, R, and S. The whirring and whining noises are about equal at the AP pump and the helm pump.

    The engine-driven pump's line runs back to the lazarette where it appears to power 2 of the steering rams, controlled by the 3rd steering ram (which is controlled by either the helm or the AP pump).

    The wheel definitely does not turn as the AP actuates. It appears to spin freely with no effect unless the AP pump is doing something, in which case the helm wheel doesn't turn. I know this sounds very strange but I'm pretty confident this was what I was seeing.

    In any case, the helm pump is heading for a rebuild today and I'll work on flushing all the old fluid from the lines and reservoir, new filter, etc. Once back together, I think the next step will be to determine if the AP pump itself is healthy.
  10. Capt Ralph

    Capt Ralph Senior Member

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    Look forward to all results. Some of us old dawgs may still learn some things.
  11. T.T.

    T.T. Senior Member

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    S.F.
    SeaMar in Seattle has a Greg Hilborn working that knows Hynautic.
    Very helpful (206)694-1125
  12. TahoeJohn

    TahoeJohn Member

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    Thank you, T.T.!! I will be giving Greg a call here if I can't get this figured out on my own.

    I finally squeezed myself back into the space where the AP pump is located and found that it was 12V, not 24V as I had previously told Dockmaster, so unfortunately I won't be able to take advantage of his incredibly generous offer. However, I did find a new AP pump in the mess of spares that came with the boat, so I'll be swapping this new one in as I flush and rebuild the system. I expect that I'll get the rebuilt helm wheel pump back by the end of this week.

    Old pump (I wiped a lot of dust off the label for the picture... I suspect it hasn't been touched since it was installed in Taiwan 20 years ago):
    old pump.jpg

    New pump:
    new pump.jpg